How can you tell the difference between cz and diamonds?

Answer 1

One quick test is the "fog test". If you can momentarily fog up the stone by breathing on it, it's probably not a diamond. This is due to diamond's exceptionally high thermal conductivity. The scratch test is not a good way to tell because CZ is hard enough to scratch most glass too, and anyhow, testing a stone in this way can cause it to crack or chip.

Other distinguishing characteristics -
Compared to CZ diamonds:
- are less dense
- are more apt to have flaws and a tinge of color
- have lower dispersion (slightly less "fire")
- have higher index of refraction

Because of the last two items, diamonds and CZ are generally cut differently.

Answer 2

For 'my' purposes by looking...(grin)
As jewellery, white diamonds have an amazing sparkle and reflect light so brightly and in a 'crisper' fashion....
Cubic zirconia (spell?) is a bit duller and 'heavier' when light goes through it.

If you have the two side by side (about the same size) you will be able to notice the difference. But once you know how it looks you will be able to see jewellery and be able to tell what it's made of.

(Never thought I would be able to tell because cz is pretty good but diamonds...wow!..... Just make sure they aren't blood diamonds from Africa because that's wrong!)

Answer 3

They are the same crystal structure and difficult to tell apart. A few years ago 60 Minutes took samples of each to jewelers and they were pathetically wrong when trying to judge which was which. To be absolutely sure, you'd need to do hardness, optical and other testing.

Answer 4

Diamonds are stronger and doesn't break easily, crystals are very fragile.