Is there an easy way to tell a real diamond from a CZ?

jeff of pa

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They say if it cuts glass. My Expierence has been ; If I pull a ring out and look at it, If I think it Might be a diamond, it turnes out to be CZ or glass. If I pull a ring out And it is a diamond, There is NO DOUBT in my mind. of course every diamond ring I'v found was? on days the sun is shining. and there was no mistaking the way they light up in the sun. ; jeff
 

Keith IL

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Jan 8, 2004
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There is no test in the field unless you buy a diamond tester,and if you do get a tester make sure it's the latest and greatest. As far as testing a diamond by cutting glass with it, worthless since glass will cut glass.
Good Hunting
 

jeremiah212

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Jan 23, 2005
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there surely is!
it was on discovery channel few months ago on the news portion called daily planet,
they showed how buy dropping the diamond in a glass of water you could instantly tell if it was genuine or not, because the density of diamond is such that it slows down the light as it passes thru it..by putting the diamond in a glass of water and sugar (the solution but be such that the consistancy of the sugar water is like syrup) a diamond will remain visabe as a zircon will become almost invisable as the density of water/sugar syrup solution more closly matches that of the zircon..

it was really increadable and easy to do in the field..\however i may have mixed up the 2, it may be that the diamond becomes nearly invisable and the zircon visable..i suggest testing for yourself with both a real and fake rock..
 

stoney56

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Oct 4, 2004
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Not always, but some companies have been putting the letters CZ inside the ring shank along w/karet marking.
 

mavrick03

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Sep 29, 2004
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other then a testor here are some quick ways to tell if a diamond is real or fake


Cubic Zirconia's are usually made of glass, but they can sparkle and shine almost as much as a real diamond can. What they can't do, however, is scratch glass. One of the most important keys to distinguishing between a real diamond and a fake one is to perform the "Scratch Test". A real diamond will scratch glass, ruby, sapphire, and even Cubic Zirconia. This is because, on the Moh's Scale, real diamonds have a hardness rating of "ten". They give them the distinction of being the hardest natural mineral known to man. Cubic Zirconia only has a rating of "eight and a half" on the Moh's Scale. It can also be scratched by a ruby or a sapphire.

Another way you can tell if a diamond is real or a fake is to give it a "Fog Test". Hold the diamond up to your mouth and breathe on it as if you were going to clean it. Then, immediately look at it and see if the fog has quickly dissipated or not. If it did, then chances are the stone is real. If the fog stays on the stone longer than a few seconds, it may well be a Cubic Zirconia.

If you hold a real diamond under a black light, it will give off a blue look. Since most of the Cubic Zirconia look - alikes don't, this could be yet another way to tell if it's real or not. Or, if you look at a diamond under a high - powered magnifying glass, you should look for tiny, thin cracks or other flaws. If the stone has them, it could well be the "real McCoy"because it's impossible to implant these typed of imperfections in a fake diamond.

i higly recomond the magnifying glass and the black light combined


Mav
 

Gold_pinger

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Mar 3, 2004
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Not all diamonds will flourese blue under a blacklight A CZ wil flourese yellow and glass will show no change. Use a good quality 10x loupe to inspect the facets. Fakes will have rounded over edges a diamond will have very sharp edges. Look for flaws, carbon specks, ect. A jeweler will test it for you most often for no charge. Beware of the ones who want to take in in back for testing. The test only takes a few minutes. If he takes it in to the back room and tells you to come back in an hour chances are it won't be the same stone you came in with. I have my own testor. If you find as many diamond rings as I do I suggest you get your own too!
 

weldermark

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Jan 17, 2005
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unless it's a super high dollar stone you should be able to see imperfection's with a loupe or magnifying glass where as most fake's are clear.
 

lobsterman

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Jan 8, 2005
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check the girdle of the stone (the outermost edge),on most artificial stones the facets are back cut a little leaving a smooth/ flat outer surface, on a real stone the girdle is a very fine sharp edge.
if you have a loose stone (one thats not in a setting), that has a brilliant cut (traditional diamond shape) if you were to roll it on edge under your finger on a table, a fake stone would roll smoothly, a real stone you will actually feel the facets click as you roll it, provided that you have a stone big enough to roll that way, hope it helps.


or you could just give it to your wife or girlfriend and if you develop a black eye you will know it was a fake. ;D ;D ;D

Pat
 

bk

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A real diamond is carbon, which is electrically conductive. A CZ being glass is an insulator (non-conductive). A simple continuity tester should be able to tell you if it is a real diamond.
Testing it to see whether it will scratch glass or not is bogus because glass will scratch glass.
 

OP
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omnicognic

omnicognic

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Jan 22, 2005
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Thanx for all the great info, and thanx for those cool links maverick! I didn't know you could buy a tester like that! Now I know! ;D
 

lab rat

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CZ should NOT be confused with glass. CZ is Cubic Zirconia, chemistry is zirconium oxide, crystallized in a cubic structure under intense (3000 degrees) heat with the addition of a trace amount of yttrium. (This material does not occur in nature.) Glass is silicon peroxide (sometimes with lead or other metals added to increase the refractive index), and has NO crystal structure. Diamond is elemental carbon, crystallized in a cubic structure under intense pressure (20 kBar) (and also synthesized in a vacuum with NO pressure).

I prefer to rely on a 30x microscope or loupe, and look carefully at the facets. CZ facets usually are rounded, or sometimes crudely cut. Diamond facet edges are always clear and sharp. Look carefully at the culet (the point at the bottom) and see if it is broken. Diamonds break in 'stair-step' fractures, or cleave into flat planes. CZ breaks in conchoidal (scalloped or circular) fractures, similar to glass.

Diamond testers operate on the principle that diamonds are excellent conductors of heat, similar to metal. The probe tip is heated by the instrument, and when you touch it to a material the instrument measures how fast the heat dissipates. (One reason diamonds are sometimes referred to as 'ice'.) You can by a tester for somewhere on the order of $100+. I have seen them on Ebay, and you can get them from the Gemmological Institute of America (link follows):

http://www.gia.edu/

Additionally, you can get carborundum scribes (used for scoring metal) that have a hardness of about 9.5, and these could be used for testing diamonds by scratching the suspect material. Of course, if it is NOT a diamond, you run the risk of putting a nasty scratch on something that might otherwise have some aesthetic value.
 

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