How can I tell if a diamond is real?

[blike]

Someone I know recently came across a diamond earing in a parking lot. How can I tell (without a microscope) if it's real? Are there any chemical tests? What about physical tests (i.e. weight to volume ratio)...

[bloodhound]

i think the way to test is to see how much it slows down light

[Gilded]

With diamonds usually being so small, I don't think you'll be doing any weight calculations too easily. Bet you could try burning it, and if it transforms into carbon dioxide, you just had yourself a diamond that's now gone. Also, hardness tests are a good method. You could try and scratch it with corundum, or scratch corundum with it, as diamond is 10 on Mohs scale and corundum is 9.

[5614]

its not that easy to do without some kinda specialist something... microscope, measuring equipment or something... you could just take it to a jewlers and ask them.

[ecoli]

A quick test...scratch it against glass, if it doesn't scratch it, it's not a diamond.

[5614]

well that is assuming its not any hard material.... what substitutes are used in fake diamonds? (probably a variation - but which is most common?)

[bloodhound]

doest glass scracth glass?

[5614]

if you rubbed two flat planes of glass against each other neither would scratch... but if you had a sharp piece of glass and rubbed it against some other glass it could scratch (i think).

 

why? do you reckon that the fake diamond is made of glass? i doubt it because glass is too delicate.. wouldnt you use some kinda plastic or something? but then that's a bit cheap... hence i asked "what substitutes are used in fake diamonds?"

[bloodhound]

of course if u run any two smooth surfaces together it wont scratch. the whole point of the scracth test is to test the sharp edge of the possible diamond against smooth glass (i think)

[Artorius]

its easy to tell.....take it the jewellers jeeeezzzz!!!!

[Sayonara]

You'll need a great deal of experience as well as the right tools.

 

http://www.ehow.com/how_15171_avoid-buying-fake.html

 

http://www.pagewise.com/diamond-real-fake.htm

[TWJian]

Alright,how to determine whether a diamond is artificial or real?Both are the same chemically and physically.The only difference is that a real diamond splits more easily(hence it can be cut easily).

[Lance]

I think cubic zirconium is pretty hard. Im pretty sure it would scratch glass.

[ecoli]

I just meant, that if it doesn't scratch glass, it's not a diamond. However, if it does scratch glass, it may or may not be a diamond.

[Nave]

yea cubic zirconium is what they use for fake dimond. I herd this story about a girls diamond chipping in a ring...well we know thats not a real diamond.. but the glass test wont work cuz diamonds scratch glass but some substitues can too. maybe this will come in handy

The fog test. Put the rock in front of your mouth and fog it like you would try to fog a mirror. If it stays fogged for 2-4 seconds, it’s a fake. A real diamond disperses the heat instantaneously so by the time you look at it, it has already cleared up. (A down fall to this test is oil and dirt on the stone can effect its reliability and the test is not accurate at all on doublets where the top of the stone is diamond and the bottom is cubic zirconia epoxied together.)

[bloodhound]

I just meant, that if it doesn't scratch glass, it's not a diamond. However, if it does scratch glass, it may or may not be a diamond.

so that test goes out the window..

[Nave]

you could do it by weight.. cubic zirconium is about 55% heavyer then a real diamond i belive but i dont know if the carot would come into effect with that

[coquina]

Buy a jewels loop - not very expensive and a useful tool.

 

First off - diamonds are graded by the 3 C's - color, clarity, and cut.

The "perfect white diamond" is not tinged with color, has no inclusions, and has been cut perfectly so that the chrystaline structure refracts the maximum amount of light.

 

Color - the "perfect" white diamond is not a shade of gray it is transparent.

 

Industrial diamonds are almost black, the best gem quality diamonds are almost clear. The operative word is "almost" - it is exceedingly rare to find a natural diamond that doesn't have some inclusions - which can be seen as little black specks through the loop. If you see specks, it might not be a perfect diamond, but in all probability, it is not a fake.

 

Cut - there are several forms of cut, but natural diamonds, because of their hardness, must be cut - that means there should be very keen edges. If it is glass, it was probably poured into a mould and the edges will appear transparent.

 

As far as cutting glass, a diamond will cut it, but so will a ruby or sapphire.

Here's the Moh's scale http://www.amfed.org/t_mohs.htm

- anything with a higher number will scratch anything with a lower number. Corundum - ruby and sapphire, is the material that is below diamond on the hardness scale. Sandpaper for metal working in made from the industrial grade of this material (don't use the ones made for wood - they are aluminum oxide or garnet).

 

If you rub your stone on a piece of corundum sand paper, and it is scratched, it is not a diamond.

[JohnB]

The "colour" part of the three c's is starting to go by the board a bit. The rarest diamonds are the Argyle Pink diamonds, which while coloured have a beautiful clarity.

 

Also the blue and green diamonds are staging a bit of a comeback with the rise of exceptionally good artificial sapphires and emeralds. The best fakes can only be detected with an extremely powerful microscope as they can pass any other test.

[Gilded]

http://www.thaigem.com/buyer_diamond.asp - A very comprehensive guide to buying and identifying diamonds. Check out the moissanite part - they're used quite often as fake diamonds.

[badchad]

I have a question thats a bit off-topic. I have an older coffee table with a glass top. Since it's somewhat older, the glass top has some scratching on it. How does this happen if a diamond is one of the only things that can cut glass?

[Sayonara]

Because diamond isn't one of the only things that can scratch glass. The point that was made is that most diamond substitutes won't cut glass. See post #14.

[YT2095]

Because diamond isn't one of the only things that can scratch glass.

he`s right, the roller blades in a glass cutter are treated metal discs

[coquina]

If you go back and read what I wrote, you will see that I stated the perfect "white diamond". Colored diamonds - canaries, or pinks, or blue - like the Hope diamond, can be much more valuable than the ordinary colorless, or white diamond.