jdmyprez_deo_vindice
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This was actualy split from another thread I did on buying precious metals at public auction. You can access that thread here: http://www.ronpaulforums.com/showthread.php?t=262478
A forum vet asked that I do a write-up on identifying jewelry and I thought maybe I should also provide it as a split thread since many of you may wish to invest in precious stones or precious metals in jewelry form. Many of the rules for buying PM's in the original thread apply here with only a few differences (namely, you will have to compete with the little old ladies at estate sales where with coins they will leave you alone) but most of the rest of it applies. So I hope someone can make use of this and make a good investment for pennies on the dollar.
Jewelry can be tricky business but there are quite a few ways which you can avoid being burned on the auction block. First I can give you a good list of tools that you should acquire and keep in your car at all times.
TOOLS
Jeweler's Loupe - These can be purchased online for as little as $14.99 and I would suggest getting one that you can hang around your neck with at least 25x magnification capabilities. These are very important as many times it is almost impossible to see the makers mark or other important marks that may be on the piece in question. These will also allow you to spot possible damage areas such as old breaks or modifications of bands, chips in stones, etc.
BABY WIPES - This may sound stupid at first but many times (especially at estate sales) you will encounter jewelry that has not been cleaned in decades and in order to do some of the tests that will follow, you will need the item to be clean.
PEN BLACKLIGHT - These can be purchased for about the same amount as a respectable loupe. Many modern chemicals (and even old chemicals) used in jewelry repair and alteration will glow when exposed to blacklight so even if it is not visible with a loupe you will want to scan a potentially valuable piece with a blacklight (tip.. this also works with antique textiles, glassware and artwork).
PEN FLASHLIGHT - Many auction galleries will have poor lighting and this will assist you with viewing the piece in question in low light areas. This can also be used to test the refractive quality of certain stones which can help determine authenticity.
LASER TESTER - This is not absolutely necessary and they can be very expensive but if you plan on becoming a major estate jewelry buyer than this will save a lot of time and effort. A great one will be able to test for silver, gold, platinum, palladium, diamond, onyx, ruby, emerald, pearl, mother of pearl, etc. I will give you other methods to test for these items as one of these units (a good one anyway) is typically out of reach for the casual dealer.
A LIGHTER - Some types of jewelry can be tested with heat and you can use a lighter in combination with the next tool which is a:
SEWING NEEDLE - Some types of jewelry can be tested by poking it with a hot needle.
MAGNET - You can use a small magnet to test for authenticity of certain types of metals.
Now that you have a breakdown of basic tools you will need, we can move on to different types of jewelry you will encounter.
TYPES
PRECIOUS STONES - For the purposes of this I will focus on the most commonly encountered which are Diamond, Ruby, Emerald, Onyx, Opal, Amethyst and for the sake of time and space I will include pearl in this.
PRECIOUS METALS - You will find many basic bands, chains as well as necklace and bracelet charms of made of either gold, silver or platinum and since those are the most common, I will stick with those.
COSTUME JEWELRY - I will include some info on some of this because there are some very collectible costume jewelry pieces made from certain non precious materials and there are ways to determine the real deal from the fakes.
Those are the three major types of jewelry you will encounter and virtually everything you see will fall into one or two of those categories. So now we can move into the details of how to tell the valuable from the junk.
DIAMONDS
Diamonds can be scary to get into but there are a few tips and tricks which really help. The first rule of thumb to use is what I call the compatability test. If it looks like a diamond but it is on a silver band or a gold band of less than 14k than the diamonds are either really small or they are not real. Jewelry makers going back to ancient times have put precious stones on precious metal bands and it is rare that you see a quality stone on a non precious metal or a high quality precious metal band. This rule applies to all precious stones and precious metal bands with stone placements.
THE CUT TESTThe first tip is obvious. We have all heard that real diamonds can cut glass and this is true but modern cubic zirconias are made so well that they can do the same thing so this tip only applies to true antique pieces. I would reccomend this as a last resort because you run a real risk of damaging the stone.
THE READING TEST - Because of the refractive nature of natural diamonds, you cannot clearly read through them whereas with fake stones you can. If you can clearly read something by looking at it through the stone than you do not have a real diamond.
FOG TEST - Natural diamonds do not conduct heat so if you breathe on a stone and it remains foggy for more than a second or two than you do not have a real diamond.
WEIGHT TEST - This one can be tricky but you can practice and learn to feel the difference. CZ stones have a greater density than natural diamonds and thus a CZ stone that is the exact same size as a natural diamond will weigh slightly more than the diamond. Through practice you can learn to tell the difference.
FLUORESCENCE TEST - This is where you can make first use of that blacklight pen. When held under a blacklight, a CZ stone will not cast a real noticeable blue fluorescence whereas a natural diamond will give off a blue fluorescence. The one drawback here is that the better quality the diamond the less of a blue hue you will see so if you examine a piece and you do not see a real brilliant fluorescence yet you still feel that it could be the real deal than go to other testing methods.
LOUPE TEST - You can use a loupe to inspect the girdle of the setting. The girdle is where the stone's pavillion (the part of the stone hidden by the setting) and crown (part of the stone above the setting) meet. If this area looks somewhat frosty in color under a loupe than you likely have a real diamond however it it looks sort of waxy in that area under the loupe than the odds are that you are looking at a fake. You can also use a loupe to look for a dead giveaway with CZ stones and that giveaway is that many modern CZ stones are almost microscopically engraved or laser etched "C.Z." inside of the stone. If you see that mark than you know you are dealing with a cubic zirconia.
PAVILLION TEST - This is not 100% but more often than not it holds true. If you look at the pavillion of the setting (again, the area of the setting that hides the bottom of the stone) you should see it has a hole cut into the metal. Jewelry makers cut the very bottom out for diamonds because they want it to catch as much light as possible, making it sparkle. With CZ stones they rarely do this.
RUBY
There are not as many ways to determine real rubies from fakes but the good news is that you are not as likely to run into fake rubies on the auction block though they certainly do exist. Here are a few tips to help you determine the real deal from the fakes or the lab created.
CUT TYPE TEST - Almost all rubies over 1 carat are cut in oval or cushion cuts. It would help to get to know the different types of cuts before you go out as this is the number one indicator between the real deal and faux stone. If you are looking at a big stone with a simple cut than it is not a ruby.
PAVILLION TEST - Rubies like diamonds will only rarely feature a closed pavillion. Most of them will come with open backs where you will see a small hole to allow as much light into the stone as possible. They do not go through this trouble for fake rubies as they will not be as refractive anyway.
TINY BUBBLE TEST - This is where your loupe is going to come in handy. A real ruby should be nice and clear inside. If you notice any tiny bubbles or streaks inside of the stone than you are looking at a fake or a lab created ruby.
EDGE TEST - A real ruby is cut with nice, clean cut, sharp edges on the stone whereas fakes are nice and smooth.
EMERALDS
These are sort of like rubies in that there are limited tests to tell the difference easily at an auction house but there are a few that will never fail you.
REVERSE RUBY TEST - You may remember that with rubies, if you saw any flaws inside of the stone by using a loupe than you were probably dealing with a fake. Well it is the exact opposite here. Natural emeralds will have streaks, tiny bubbles and imperfections inside of the stone. You might also see black spots inside of very high quality emeralds because of the high amount of carbon in emeralds. You will not see black spots at all in any fake or lab created emeralds.
PAVILLION TEST - Natural emeralds will also have an open back pavillion to allow as much light as possible to shine through the stone. This is not always the case but more often than not this holds true.
ONYX
Onyx is virtually impossible to test without a professional tool (at least this is my experience). There are two pieces of good news here though. Onyx is not overly expensive so there has not been a strong demand for fakes so odds are you will be looking at the real deal.
OPAL
The biggest problem you face here is people using dyes to turn less desireable colors into black opal which is the most commercially desireable. There are really only two tests needed to determine real opals from those that are fake or have been modified.
BUOYANCY TEST - This test is designed to identify the opals that have been dyed. The bad part is that there is no practical way you can do this at the auction house. The process used to dye opals makes them somewhat buoyant so ones that have been dyed and then placed into a pot of water will attempt to float whereas natural, unmodified stones will not.
HEAT TEST - Here is the first test where that lighter and sewing needle will come in handy. If you are confronted with an opal that you are not sure is genuine than heat up the tip of the needle for about 20 seconds and the poke the stone. If the tip of the needle penetrates the stone slightly than you do not have a real opal and the real deal would not be effected by such a test.
AMETHYST - There are two sure fore methods to determine real amethyst in jewelry.
SURFACE COLOR TEST - Natural amethyst will be almost clear in the center while the surface will be colored and shining a light through this stone will create an almost prism effect. Faux stones will be solidly colored and will lack the prism effect.
INTERIOR FLAW TEST - Again you will be using your loupe. A natural amethyst will have at least a few interior bubbles, tiny interior cracks or other imperfections, if the stone lacks these features than it is either fake or lab grown.
PEARL
Pearls are of course not an actual stone but for the purposes of this tutorial I will treat them as such. Pearls are perhaps the most faked mineral in the jewelry business and it can be tricky telling the real from the fake but here are a few to help you out in your travels.
TOOTH TEST - I would not suggest doing this where people can see you which may make this test difficult at time. Natural pearls have a natural gritty feel to them due to the irregularities the layers of nacre (which make up a pearl) contain. A real pearl will feel gritty when rubbed against a tooth whereas a fake one or one cultured in a lab will feel very smmoth against your tooth.
THE BODY HEAT TEST - Pearls are not natural conductors of heat. What you can do is hold a suspect pearl against your cheek for 30 seconds and then remove it and place it on the opposite cheek. If it feels nice and cold than you very well may have a pearl but if it feels close to body temperature than you are not holding a natural pearl.
THE LIGHT TEST - Natural pearls when held under sunlight or a pen light will show different levels of iridescence on each stone due to the variations of the nacre. Simulated pearls will not have this feature and each faux pearl will look the same in bright lighting.
DRILL HOLE TEST - Examine the drill holes on the pearl. Natural pearls are valued by weight so obviously the jeweler wants to preserve as much of that weight as possible. So if it has very tiny holes than it is a good indication it is the real deal whereas if the holes are large than they are more than likely fake. the drill holes on real pearls are also typically drilled from two side leaving both holes of equal size. On fake pearls, the jeweler typically drills straight through leaving one hole slightly bigger than the other. You can also examine the edges of the holes for clues. The edges around the drill holes of real pearls are rarely chipped or flaked whereas fakes chipe and flake easily.
SURFACE LOUPE TEST - By using your loupe you can see the irregularities in the surface of real pearls whereas fakes will look nice and smooth even under a loupe.
WEIGHT TEST - Natural pearls are heavier than the fakes. This is a test that you will have to learn through experience.
VISUAL TEST - Examine the strand the pearls are on. Real pearls typically have small knots in the strand between each pearl whereas you will typically not see this on the fakes. Also examine the settings or the clasp. On real pearls, these will be made of precious metals and not plastic or stainless steel.
Those are the most common precious stones you will encounter on the auction block and now that you know some tricks for that we can move on to the precious metals.
GOLD
There are a few ways to determine real gold without having to resort to very expensive testing methods.
MARK TEST - Gold producers are proud of the fact that they produce it so they mark it. I will delve further into this in the markings section.
SIGHT TEST - Fake gold tends to have a real yellowish shine to it whereas real gold has more of a satin look to it. This is something you will have to learn through experience.
PLATING TEST - Items that are just gold plated will generally be marked as such (more in the marking section) and one way you can tell from antique jewelry is to look for areas of wear.. Use your pen light to shine around the piece and look for any areas that give off a silvery sheen.. If you see that than you have a piece that is only gold plated.
NITRIC ACID TEST - This is another one that you cannot practically perform at the location so you will have to do this at home. Get a bottle of nitric acid (can get it relatively cheap online). Drop a few drops of nitric acid onto the suspect piece. If it is real gold than it will do nothing but fake gold will darken in color.
MAGNET TEST - If a magnet sticks to the piece than it is not gold as gold is non magnetic.
SILVER
Silver is typically pretty easy to test and after awhile you will be able to spot the real from the fake without even having to test but for now here are a few tips to tell the real from the fake.
MARK TEST - Most modern silver (silver since the late 1800's) is clearly marked as such. More on this in the marking section.
WEIGHT TEST - Silver is a very light metal and as such will weigh next to nothing whereas something that is silver plated or just colored silver will have a considerable weight.
MAGNET TEST - If the magnet sticks to the suspected piece than it is not silver as silver is non magnetic.
PLATINUM
You do not see a ton of jewelry (especially antique jewelry) made from platinum but you do see it on occasion. Here are a few ways to tell the real deal from the faux crap.
SIGHT TEST - Platinum (unless altered) will have a silver appearance that borders on being white. If it looks too much like silver than it is not pure platinum.
SCRATCH TEST - Platinum is the most durable of the precious metals so if you see a piece that you suspect is platinum and it has numerous scuffs or scratches than odds are it is not platinum as platinum does not easily scratch.
CORROSION TEST - Platinum is naturally corrosion resistant so if you come across a suspected piece that shows signs of corrosion than it is not real platinum.
WEIGHT TEST - Platinum is roughly twice as heavy as gold. If you suspect a piece is platinum and it is light than it is not true platinum.
COSTUME JEWELRY
I am including a section on this because costume jewelry has taken on a strong market in recent years and in some instances there are pieces of costume jewelry that have a greater value than pieces made from precious metals and stones. Now as far as particular makers, that market changes rapidly and what was popular in the collectors market yesterday may not be today so I would just keep up to date on what is selling (one tip... avon jewelry will never be worth a penny so avoid it). The two areas of costume jewelry that are always valuable and in string demand are pieces made of bakelite and catalin plastic. So bear with me and I will give you a back ground on what these materials are.
BAKELITE
Bakelite was one of the early plastic formulas used in mass production and was invented sometime prior to 1910. It became very popular around ww2 when American forces realized how durable goods made by the Nazis were compared to American war materials. So that knowledge led to a real boom in bakelite production (there was a slight boom in the 30's as well) and soon enough almost everything that could be made of bakelite was.. radios, film projectors, dinnerware and yes, even jewelry. Bakelite jewelry has a very strong collectors market and you can quite often see it coming out of estates. So how do you tell bakelite plastic jewelry from plain old uninteresting plastic jewelry? You can use these tips to help you out:
SOUND TEST - If you tap together two pieces of bakelite they will make a deep thud sound whereas regular plastic will sound much higher pitched when clanged together.
WEIGHT TEST - Bakelite was made from a phenolic resin which is much denser than the resin used to make regular and modern plastics. So the weight of a bakelite piece will be heavier than one made from regular plastic.
HEAT AND SNIFF TEST - You can use two methods here... You can either rub the piece vigorously with your finger or you can hold it close enough to a flame to make it hot yet far enough away not to melt it and then smell it. One of the ingredients in bakelite was formaldehyde which puts off a very distinct smell. You will be able to clearly smell this when bakelite is heated up.
METAL POLISH TEST - Take a soft cloth and smear some metal polish (I suggest simichrome as it seems to work best for this) and rub an inconspicuous area of the suspected bakelite. If it is real bakelite than the cloth will start to turn yellow (This will not be the case with bakelite that is black or was lacquered). Be sure to wash the piece off when you are done.
FORMULA 409 TEST - You can put a small amount of formula 409 on a cotton swab and use the same process as you did with the metal polish. Again, the swab should turn yellow if it is bakelite (again this will not work if the piece is black or was lacquered). be sure to wash the piece when you are done.
SCRATCH TEST - You will use your loupe for this one. Bakelite was durable but prone to scratching (which is one of the reasons for it's downfall as the plastic of choice). Real bakelite will have tiny scratches visible with the use of a loupe.
CATALIN
Catalin plastic is/was a very specific type of plastic that was made the same way as bakelite but with slight formula changes that allowed it be made into a very bright and attractive material. Catalin was very expensive to produce and this items made from catalin were scarce and catalin products are highly sought after by collectors today with some items bringing into the tens of thousands. Catalin jewelry was not really mass produced but you can occasionally find it especially from higher class estates as it was very expensive to acquire. All of the methods used to determine the authenticity of bakelite can apply to catalin except for these additional testing methods:
DENSITY TEST - Catalin was very dense and when it solidified was as hard as brass. Catalin jewelry will be heavy and will feel very thick.
COLOR TEST - Unlike bakelite, catalin was very bright and festive looking. If an item tests as bakelite but is very bright looking than you have found a catalin piece.
Those tests should be able to help you feel more secure in your purchases but t fully feel safe with buying jewelry at auction it helps to have a good understanding of the different marks you might encounter. Some of these you will know but I will include them anyway.
MARKS
Marks can be hard to find on some pieces and you will need your loupe to find the marks on most pieces. On rings, you will usually find the mark inside of the bands though rarely you can find a mark on the pavillion. On necklaces and bracelets you will almost always find the mark on the clasp. On charms you will typicaly find the mark on the back of the charm.
k - You will find a "K" mark on pieces of gold jewelry preceeded by various numbers (10,14,18,22 and 24 being the most common). The "K" stands for Karat which is how you measure the purity of a gold alloy. The higher the number preceeding the "K" the greater the purity (each carat represents 1/24th purity by mass). 24k is the best mark you can hope to see as that represents a 99.9% millesimal fineness. You will not see higher than 24k in jewelry because of the pliability of pure gold. This pliability requires gold jewelry to be mixed with at least a 0.01% base metal formula (usually copper). Bear in mind that some foreign nations (India especially) use a different Karat system than we do and 22k is their version of our 24k so learning styles can be important.
STERLING - Sterling is a mark you will see on silver pieces. Sterling silver is the highest purity marker for silver you will find. Because of how pliable silver is (much more so than gold in pure form) silver 92.5% silver and the rest is base metal (usually copper). The word sterling originated sometime in the 12th century in Europe as a means of identifying pieces that were 92.5% pure silver.
.925 - This is another mark that indicates 92.5% pure silver. Most makers use a mark of "sterling" but some makers prefer to use .925 which means the same thing.
.925/1000 - Yet another mark that says the piece you are looking at it 92.5% pure silver. You do not see this mark on a regular basis.
G.P. - This stands for gold plated. You have to be very careful with gold plated pieces as many times you will see an item marked as if it were real gold and it might appear as "14k" and engraved in very small letters behind it will be the "g.p." mark. Gold plating simply means that the majority of the piece is a base metal (usually copper) and only a very thin layer of gold was used on the surface.
S.P. - This stands for silver plated which means that the mass of the piece is a base metal (usually copper) with only a thin layer of silver on the surface.
P.P. - This stands for Platinum Plated which means the mass of the piece is a base metal (usually copper) with only a very thin layer of platinum on the surface.
E.G.P. - This stand for electro gold plated and simply indicates that the piece is gold plated but was done by electroplating.
E.S.P. - Same as above except the "S" stands for silver
E.P.P. - Same as above except the first "P" stands for platinum.
Platinum - Will be marked on pieces that are at least 95% pure platinum. These marks may also appear as "plat." or "platine".
N.P. - You will occasionally see this on pieces of jewelry and it stands for Nickle Plated which just means this is about the cheapest piece of junk jewelry you will ever find.
COIN - If you see an item stamped "coin" than you have a piece of silver that was produced between the early colonial period in America up until a few years after the American Civil War. In those days, silversmiths were common and it was much cheaper to have a silversmith melt down your silver coins than it was to buy a piece of sterling from Europe. So the silversmiths would melt down the coins and mold the molten silver into items such as pocket watch cases, candle sticks, silverware and jewelry. Many times the silversmith would mark the piece in block letters that said "coin" which stood of course for coin silver. In most instances, coin silver is over 95% pure and in some instances it has a higher silver content than sterling. Sadly, not all pieces were marked with "coin" and were only marked with a makers mark and so you have to really know early american silversmithing, obtain a good knowledge of marks and rely upon other testing methods to determine that it is in fact silver.
MAKERS MARKS
There are literally thousands of companies active today making jewelry not to mention the hundreds of thousands that have done so throughout history so a concise guide on makers marks on this forum are nearly impossible. There are many guides out there which you can purchase that will have a list and illustrations of the most common marks you will find. The good news that most makers since around the end the American Civil War have simplified the marking process and will mark the piece with either the company name, the designer name or a company logo. Prior to that you really have to have some knowledge or a good guide and knowledge will only come with experience. There were thousands upon thousands of marks ranging from the simple crown on up to horses jumping over a fence with a rider holding a spoon. So if anyone finds a piece that they question than just send me an image of it and I will help you identify it.
So I hope that this will help you feel comfortable with buying jewelry at auction and if nothing else, you can enjoy the hunt for valuable pieces for pennies on the dollar.
A forum vet asked that I do a write-up on identifying jewelry and I thought maybe I should also provide it as a split thread since many of you may wish to invest in precious stones or precious metals in jewelry form. Many of the rules for buying PM's in the original thread apply here with only a few differences (namely, you will have to compete with the little old ladies at estate sales where with coins they will leave you alone) but most of the rest of it applies. So I hope someone can make use of this and make a good investment for pennies on the dollar.
Jewelry can be tricky business but there are quite a few ways which you can avoid being burned on the auction block. First I can give you a good list of tools that you should acquire and keep in your car at all times.
TOOLS
Jeweler's Loupe - These can be purchased online for as little as $14.99 and I would suggest getting one that you can hang around your neck with at least 25x magnification capabilities. These are very important as many times it is almost impossible to see the makers mark or other important marks that may be on the piece in question. These will also allow you to spot possible damage areas such as old breaks or modifications of bands, chips in stones, etc.
BABY WIPES - This may sound stupid at first but many times (especially at estate sales) you will encounter jewelry that has not been cleaned in decades and in order to do some of the tests that will follow, you will need the item to be clean.
PEN BLACKLIGHT - These can be purchased for about the same amount as a respectable loupe. Many modern chemicals (and even old chemicals) used in jewelry repair and alteration will glow when exposed to blacklight so even if it is not visible with a loupe you will want to scan a potentially valuable piece with a blacklight (tip.. this also works with antique textiles, glassware and artwork).
PEN FLASHLIGHT - Many auction galleries will have poor lighting and this will assist you with viewing the piece in question in low light areas. This can also be used to test the refractive quality of certain stones which can help determine authenticity.
LASER TESTER - This is not absolutely necessary and they can be very expensive but if you plan on becoming a major estate jewelry buyer than this will save a lot of time and effort. A great one will be able to test for silver, gold, platinum, palladium, diamond, onyx, ruby, emerald, pearl, mother of pearl, etc. I will give you other methods to test for these items as one of these units (a good one anyway) is typically out of reach for the casual dealer.
A LIGHTER - Some types of jewelry can be tested with heat and you can use a lighter in combination with the next tool which is a:
SEWING NEEDLE - Some types of jewelry can be tested by poking it with a hot needle.
MAGNET - You can use a small magnet to test for authenticity of certain types of metals.
Now that you have a breakdown of basic tools you will need, we can move on to different types of jewelry you will encounter.
TYPES
PRECIOUS STONES - For the purposes of this I will focus on the most commonly encountered which are Diamond, Ruby, Emerald, Onyx, Opal, Amethyst and for the sake of time and space I will include pearl in this.
PRECIOUS METALS - You will find many basic bands, chains as well as necklace and bracelet charms of made of either gold, silver or platinum and since those are the most common, I will stick with those.
COSTUME JEWELRY - I will include some info on some of this because there are some very collectible costume jewelry pieces made from certain non precious materials and there are ways to determine the real deal from the fakes.
Those are the three major types of jewelry you will encounter and virtually everything you see will fall into one or two of those categories. So now we can move into the details of how to tell the valuable from the junk.
DIAMONDS
Diamonds can be scary to get into but there are a few tips and tricks which really help. The first rule of thumb to use is what I call the compatability test. If it looks like a diamond but it is on a silver band or a gold band of less than 14k than the diamonds are either really small or they are not real. Jewelry makers going back to ancient times have put precious stones on precious metal bands and it is rare that you see a quality stone on a non precious metal or a high quality precious metal band. This rule applies to all precious stones and precious metal bands with stone placements.
THE CUT TESTThe first tip is obvious. We have all heard that real diamonds can cut glass and this is true but modern cubic zirconias are made so well that they can do the same thing so this tip only applies to true antique pieces. I would reccomend this as a last resort because you run a real risk of damaging the stone.
THE READING TEST - Because of the refractive nature of natural diamonds, you cannot clearly read through them whereas with fake stones you can. If you can clearly read something by looking at it through the stone than you do not have a real diamond.
FOG TEST - Natural diamonds do not conduct heat so if you breathe on a stone and it remains foggy for more than a second or two than you do not have a real diamond.
WEIGHT TEST - This one can be tricky but you can practice and learn to feel the difference. CZ stones have a greater density than natural diamonds and thus a CZ stone that is the exact same size as a natural diamond will weigh slightly more than the diamond. Through practice you can learn to tell the difference.
FLUORESCENCE TEST - This is where you can make first use of that blacklight pen. When held under a blacklight, a CZ stone will not cast a real noticeable blue fluorescence whereas a natural diamond will give off a blue fluorescence. The one drawback here is that the better quality the diamond the less of a blue hue you will see so if you examine a piece and you do not see a real brilliant fluorescence yet you still feel that it could be the real deal than go to other testing methods.
LOUPE TEST - You can use a loupe to inspect the girdle of the setting. The girdle is where the stone's pavillion (the part of the stone hidden by the setting) and crown (part of the stone above the setting) meet. If this area looks somewhat frosty in color under a loupe than you likely have a real diamond however it it looks sort of waxy in that area under the loupe than the odds are that you are looking at a fake. You can also use a loupe to look for a dead giveaway with CZ stones and that giveaway is that many modern CZ stones are almost microscopically engraved or laser etched "C.Z." inside of the stone. If you see that mark than you know you are dealing with a cubic zirconia.
PAVILLION TEST - This is not 100% but more often than not it holds true. If you look at the pavillion of the setting (again, the area of the setting that hides the bottom of the stone) you should see it has a hole cut into the metal. Jewelry makers cut the very bottom out for diamonds because they want it to catch as much light as possible, making it sparkle. With CZ stones they rarely do this.
RUBY
There are not as many ways to determine real rubies from fakes but the good news is that you are not as likely to run into fake rubies on the auction block though they certainly do exist. Here are a few tips to help you determine the real deal from the fakes or the lab created.
CUT TYPE TEST - Almost all rubies over 1 carat are cut in oval or cushion cuts. It would help to get to know the different types of cuts before you go out as this is the number one indicator between the real deal and faux stone. If you are looking at a big stone with a simple cut than it is not a ruby.
PAVILLION TEST - Rubies like diamonds will only rarely feature a closed pavillion. Most of them will come with open backs where you will see a small hole to allow as much light into the stone as possible. They do not go through this trouble for fake rubies as they will not be as refractive anyway.
TINY BUBBLE TEST - This is where your loupe is going to come in handy. A real ruby should be nice and clear inside. If you notice any tiny bubbles or streaks inside of the stone than you are looking at a fake or a lab created ruby.
EDGE TEST - A real ruby is cut with nice, clean cut, sharp edges on the stone whereas fakes are nice and smooth.
EMERALDS
These are sort of like rubies in that there are limited tests to tell the difference easily at an auction house but there are a few that will never fail you.
REVERSE RUBY TEST - You may remember that with rubies, if you saw any flaws inside of the stone by using a loupe than you were probably dealing with a fake. Well it is the exact opposite here. Natural emeralds will have streaks, tiny bubbles and imperfections inside of the stone. You might also see black spots inside of very high quality emeralds because of the high amount of carbon in emeralds. You will not see black spots at all in any fake or lab created emeralds.
PAVILLION TEST - Natural emeralds will also have an open back pavillion to allow as much light as possible to shine through the stone. This is not always the case but more often than not this holds true.
ONYX
Onyx is virtually impossible to test without a professional tool (at least this is my experience). There are two pieces of good news here though. Onyx is not overly expensive so there has not been a strong demand for fakes so odds are you will be looking at the real deal.
OPAL
The biggest problem you face here is people using dyes to turn less desireable colors into black opal which is the most commercially desireable. There are really only two tests needed to determine real opals from those that are fake or have been modified.
BUOYANCY TEST - This test is designed to identify the opals that have been dyed. The bad part is that there is no practical way you can do this at the auction house. The process used to dye opals makes them somewhat buoyant so ones that have been dyed and then placed into a pot of water will attempt to float whereas natural, unmodified stones will not.
HEAT TEST - Here is the first test where that lighter and sewing needle will come in handy. If you are confronted with an opal that you are not sure is genuine than heat up the tip of the needle for about 20 seconds and the poke the stone. If the tip of the needle penetrates the stone slightly than you do not have a real opal and the real deal would not be effected by such a test.
AMETHYST - There are two sure fore methods to determine real amethyst in jewelry.
SURFACE COLOR TEST - Natural amethyst will be almost clear in the center while the surface will be colored and shining a light through this stone will create an almost prism effect. Faux stones will be solidly colored and will lack the prism effect.
INTERIOR FLAW TEST - Again you will be using your loupe. A natural amethyst will have at least a few interior bubbles, tiny interior cracks or other imperfections, if the stone lacks these features than it is either fake or lab grown.
PEARL
Pearls are of course not an actual stone but for the purposes of this tutorial I will treat them as such. Pearls are perhaps the most faked mineral in the jewelry business and it can be tricky telling the real from the fake but here are a few to help you out in your travels.
TOOTH TEST - I would not suggest doing this where people can see you which may make this test difficult at time. Natural pearls have a natural gritty feel to them due to the irregularities the layers of nacre (which make up a pearl) contain. A real pearl will feel gritty when rubbed against a tooth whereas a fake one or one cultured in a lab will feel very smmoth against your tooth.
THE BODY HEAT TEST - Pearls are not natural conductors of heat. What you can do is hold a suspect pearl against your cheek for 30 seconds and then remove it and place it on the opposite cheek. If it feels nice and cold than you very well may have a pearl but if it feels close to body temperature than you are not holding a natural pearl.
THE LIGHT TEST - Natural pearls when held under sunlight or a pen light will show different levels of iridescence on each stone due to the variations of the nacre. Simulated pearls will not have this feature and each faux pearl will look the same in bright lighting.
DRILL HOLE TEST - Examine the drill holes on the pearl. Natural pearls are valued by weight so obviously the jeweler wants to preserve as much of that weight as possible. So if it has very tiny holes than it is a good indication it is the real deal whereas if the holes are large than they are more than likely fake. the drill holes on real pearls are also typically drilled from two side leaving both holes of equal size. On fake pearls, the jeweler typically drills straight through leaving one hole slightly bigger than the other. You can also examine the edges of the holes for clues. The edges around the drill holes of real pearls are rarely chipped or flaked whereas fakes chipe and flake easily.
SURFACE LOUPE TEST - By using your loupe you can see the irregularities in the surface of real pearls whereas fakes will look nice and smooth even under a loupe.
WEIGHT TEST - Natural pearls are heavier than the fakes. This is a test that you will have to learn through experience.
VISUAL TEST - Examine the strand the pearls are on. Real pearls typically have small knots in the strand between each pearl whereas you will typically not see this on the fakes. Also examine the settings or the clasp. On real pearls, these will be made of precious metals and not plastic or stainless steel.
Those are the most common precious stones you will encounter on the auction block and now that you know some tricks for that we can move on to the precious metals.
GOLD
There are a few ways to determine real gold without having to resort to very expensive testing methods.
MARK TEST - Gold producers are proud of the fact that they produce it so they mark it. I will delve further into this in the markings section.
SIGHT TEST - Fake gold tends to have a real yellowish shine to it whereas real gold has more of a satin look to it. This is something you will have to learn through experience.
PLATING TEST - Items that are just gold plated will generally be marked as such (more in the marking section) and one way you can tell from antique jewelry is to look for areas of wear.. Use your pen light to shine around the piece and look for any areas that give off a silvery sheen.. If you see that than you have a piece that is only gold plated.
NITRIC ACID TEST - This is another one that you cannot practically perform at the location so you will have to do this at home. Get a bottle of nitric acid (can get it relatively cheap online). Drop a few drops of nitric acid onto the suspect piece. If it is real gold than it will do nothing but fake gold will darken in color.
MAGNET TEST - If a magnet sticks to the piece than it is not gold as gold is non magnetic.
SILVER
Silver is typically pretty easy to test and after awhile you will be able to spot the real from the fake without even having to test but for now here are a few tips to tell the real from the fake.
MARK TEST - Most modern silver (silver since the late 1800's) is clearly marked as such. More on this in the marking section.
WEIGHT TEST - Silver is a very light metal and as such will weigh next to nothing whereas something that is silver plated or just colored silver will have a considerable weight.
MAGNET TEST - If the magnet sticks to the suspected piece than it is not silver as silver is non magnetic.
PLATINUM
You do not see a ton of jewelry (especially antique jewelry) made from platinum but you do see it on occasion. Here are a few ways to tell the real deal from the faux crap.
SIGHT TEST - Platinum (unless altered) will have a silver appearance that borders on being white. If it looks too much like silver than it is not pure platinum.
SCRATCH TEST - Platinum is the most durable of the precious metals so if you see a piece that you suspect is platinum and it has numerous scuffs or scratches than odds are it is not platinum as platinum does not easily scratch.
CORROSION TEST - Platinum is naturally corrosion resistant so if you come across a suspected piece that shows signs of corrosion than it is not real platinum.
WEIGHT TEST - Platinum is roughly twice as heavy as gold. If you suspect a piece is platinum and it is light than it is not true platinum.
COSTUME JEWELRY
I am including a section on this because costume jewelry has taken on a strong market in recent years and in some instances there are pieces of costume jewelry that have a greater value than pieces made from precious metals and stones. Now as far as particular makers, that market changes rapidly and what was popular in the collectors market yesterday may not be today so I would just keep up to date on what is selling (one tip... avon jewelry will never be worth a penny so avoid it). The two areas of costume jewelry that are always valuable and in string demand are pieces made of bakelite and catalin plastic. So bear with me and I will give you a back ground on what these materials are.
BAKELITE
Bakelite was one of the early plastic formulas used in mass production and was invented sometime prior to 1910. It became very popular around ww2 when American forces realized how durable goods made by the Nazis were compared to American war materials. So that knowledge led to a real boom in bakelite production (there was a slight boom in the 30's as well) and soon enough almost everything that could be made of bakelite was.. radios, film projectors, dinnerware and yes, even jewelry. Bakelite jewelry has a very strong collectors market and you can quite often see it coming out of estates. So how do you tell bakelite plastic jewelry from plain old uninteresting plastic jewelry? You can use these tips to help you out:
SOUND TEST - If you tap together two pieces of bakelite they will make a deep thud sound whereas regular plastic will sound much higher pitched when clanged together.
WEIGHT TEST - Bakelite was made from a phenolic resin which is much denser than the resin used to make regular and modern plastics. So the weight of a bakelite piece will be heavier than one made from regular plastic.
HEAT AND SNIFF TEST - You can use two methods here... You can either rub the piece vigorously with your finger or you can hold it close enough to a flame to make it hot yet far enough away not to melt it and then smell it. One of the ingredients in bakelite was formaldehyde which puts off a very distinct smell. You will be able to clearly smell this when bakelite is heated up.
METAL POLISH TEST - Take a soft cloth and smear some metal polish (I suggest simichrome as it seems to work best for this) and rub an inconspicuous area of the suspected bakelite. If it is real bakelite than the cloth will start to turn yellow (This will not be the case with bakelite that is black or was lacquered). Be sure to wash the piece off when you are done.
FORMULA 409 TEST - You can put a small amount of formula 409 on a cotton swab and use the same process as you did with the metal polish. Again, the swab should turn yellow if it is bakelite (again this will not work if the piece is black or was lacquered). be sure to wash the piece when you are done.
SCRATCH TEST - You will use your loupe for this one. Bakelite was durable but prone to scratching (which is one of the reasons for it's downfall as the plastic of choice). Real bakelite will have tiny scratches visible with the use of a loupe.
CATALIN
Catalin plastic is/was a very specific type of plastic that was made the same way as bakelite but with slight formula changes that allowed it be made into a very bright and attractive material. Catalin was very expensive to produce and this items made from catalin were scarce and catalin products are highly sought after by collectors today with some items bringing into the tens of thousands. Catalin jewelry was not really mass produced but you can occasionally find it especially from higher class estates as it was very expensive to acquire. All of the methods used to determine the authenticity of bakelite can apply to catalin except for these additional testing methods:
DENSITY TEST - Catalin was very dense and when it solidified was as hard as brass. Catalin jewelry will be heavy and will feel very thick.
COLOR TEST - Unlike bakelite, catalin was very bright and festive looking. If an item tests as bakelite but is very bright looking than you have found a catalin piece.
Those tests should be able to help you feel more secure in your purchases but t fully feel safe with buying jewelry at auction it helps to have a good understanding of the different marks you might encounter. Some of these you will know but I will include them anyway.
MARKS
Marks can be hard to find on some pieces and you will need your loupe to find the marks on most pieces. On rings, you will usually find the mark inside of the bands though rarely you can find a mark on the pavillion. On necklaces and bracelets you will almost always find the mark on the clasp. On charms you will typicaly find the mark on the back of the charm.
k - You will find a "K" mark on pieces of gold jewelry preceeded by various numbers (10,14,18,22 and 24 being the most common). The "K" stands for Karat which is how you measure the purity of a gold alloy. The higher the number preceeding the "K" the greater the purity (each carat represents 1/24th purity by mass). 24k is the best mark you can hope to see as that represents a 99.9% millesimal fineness. You will not see higher than 24k in jewelry because of the pliability of pure gold. This pliability requires gold jewelry to be mixed with at least a 0.01% base metal formula (usually copper). Bear in mind that some foreign nations (India especially) use a different Karat system than we do and 22k is their version of our 24k so learning styles can be important.
STERLING - Sterling is a mark you will see on silver pieces. Sterling silver is the highest purity marker for silver you will find. Because of how pliable silver is (much more so than gold in pure form) silver 92.5% silver and the rest is base metal (usually copper). The word sterling originated sometime in the 12th century in Europe as a means of identifying pieces that were 92.5% pure silver.
.925 - This is another mark that indicates 92.5% pure silver. Most makers use a mark of "sterling" but some makers prefer to use .925 which means the same thing.
.925/1000 - Yet another mark that says the piece you are looking at it 92.5% pure silver. You do not see this mark on a regular basis.
G.P. - This stands for gold plated. You have to be very careful with gold plated pieces as many times you will see an item marked as if it were real gold and it might appear as "14k" and engraved in very small letters behind it will be the "g.p." mark. Gold plating simply means that the majority of the piece is a base metal (usually copper) and only a very thin layer of gold was used on the surface.
S.P. - This stands for silver plated which means that the mass of the piece is a base metal (usually copper) with only a thin layer of silver on the surface.
P.P. - This stands for Platinum Plated which means the mass of the piece is a base metal (usually copper) with only a very thin layer of platinum on the surface.
E.G.P. - This stand for electro gold plated and simply indicates that the piece is gold plated but was done by electroplating.
E.S.P. - Same as above except the "S" stands for silver
E.P.P. - Same as above except the first "P" stands for platinum.
Platinum - Will be marked on pieces that are at least 95% pure platinum. These marks may also appear as "plat." or "platine".
N.P. - You will occasionally see this on pieces of jewelry and it stands for Nickle Plated which just means this is about the cheapest piece of junk jewelry you will ever find.
COIN - If you see an item stamped "coin" than you have a piece of silver that was produced between the early colonial period in America up until a few years after the American Civil War. In those days, silversmiths were common and it was much cheaper to have a silversmith melt down your silver coins than it was to buy a piece of sterling from Europe. So the silversmiths would melt down the coins and mold the molten silver into items such as pocket watch cases, candle sticks, silverware and jewelry. Many times the silversmith would mark the piece in block letters that said "coin" which stood of course for coin silver. In most instances, coin silver is over 95% pure and in some instances it has a higher silver content than sterling. Sadly, not all pieces were marked with "coin" and were only marked with a makers mark and so you have to really know early american silversmithing, obtain a good knowledge of marks and rely upon other testing methods to determine that it is in fact silver.
MAKERS MARKS
There are literally thousands of companies active today making jewelry not to mention the hundreds of thousands that have done so throughout history so a concise guide on makers marks on this forum are nearly impossible. There are many guides out there which you can purchase that will have a list and illustrations of the most common marks you will find. The good news that most makers since around the end the American Civil War have simplified the marking process and will mark the piece with either the company name, the designer name or a company logo. Prior to that you really have to have some knowledge or a good guide and knowledge will only come with experience. There were thousands upon thousands of marks ranging from the simple crown on up to horses jumping over a fence with a rider holding a spoon. So if anyone finds a piece that they question than just send me an image of it and I will help you identify it.
So I hope that this will help you feel comfortable with buying jewelry at auction and if nothing else, you can enjoy the hunt for valuable pieces for pennies on the dollar.
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