Diamonds. The definitive real or fake test!

[ecain63]

Imitation diamonds are becoming more and more sophisticated and more difficult to spot. A good moissanite can have all the visible flaws of a genuine stone and will even pass the standard 'diamond tester' assessment that the likes of Ernest Jones etc use to wow the punters. But, is there a definitive way to spot a moissanite?

Answer: Yes!

We had this in last week and i wasnt so sure it was genuine. It passed the diamond tester and it looked to have all the flaws of a genuine item. But, experience can give it away where testing doesnt. It had a sort of alcoholic look about it. A bit like looking at a glass of Gin vs a glass of Water. Theres just something a little suspect about one or the other, something in the way it looks. So, how did we test it?

Firstly, to be on the safe side we had to protect the stone using borax, as we would do normally when applying direct heat to diamonds. Moissanites are pretty hardy to be honest just like diamonds, but in the same way as the genuine article the surface can burn if unprotected leaving it milky in appearance. When heated the borax turns to a clear liquid and forms a glass like protective layer over the stone.

So what happens when its heated?

20130903_181822 by niacuk, on Flickr

20130903_181816 by niacuk, on Flickr

Basically the stone turns bright green. The shoulder stones were genuine here so no issue with them but not that moody centre one. The stone will go back to white again as it cools naturally (although this one didnt for the first 4 times i heated it, but luckily it did on the 5th) but as with any stone its essential that you allow it to cool without cold shock.

And thats how you find the dodgy ones. Thats the only 100% test!

Eddie

[yeti]

That's really interesting thanks!

Didn't know they used SiC as a diamond substitute, it's pretty rare naturally - is this lab formed?

[DozyGit]

Really cool post, you learn something new everyday, thank you so much

[CardShark]

Is there any truth in being able to tell a cut real diamond from a fake by placing it on a bed of salt and looking out for changes in colour?

Not entirely sure where I picked that up from, may have been a film or something else... Could just be a load of old tosh!

Edited by CardShark on Sunday 8th September 23:05

[ecain63]

^^^^not as far as I know. Could be true, but then.........

[ecain63]

yeti said:

That's really interesting thanks!

Didn't know they used SiC as a diamond substitute, it's pretty rare naturally - is this lab formed?

Yeah, its a lab process getting them to look that good. They are still not cheap either. £500+ for a carat stone.

[toastybase]

I heard somewhere that to find out if a diamond is genuine, you draw a straight line on a piece of paper and then place the diamond on top of the line.

If the line is not distorted when you look at it through the diamond then it's a real diamond.

[Silent1]

I thought moissanite was a different colour to diamond under fluorescent light?

[ecain63]

Silent1 said:

I thought moissanite was a different colour to diamond under fluorescent light?

Worked on earlier stones, but newer ones are far more realistic.

[ecain63]

toastybase said:

I heard somewhere that to find out if a diamond is genuine, you draw a straight line on a piece of paper and then place the diamond on top of the line.

If the line is not distorted when you look at it through the diamond then it's a real diamond.

Depends on the cut. But yeah, refraction is a giveaway. However, as above they are clever little sods these days.