Cubic zirconia (CZ) is an artificially produced gemstone that is similar to diamond. When discussing it as a "diamond replacement", I have often seen the claim that it is inferior because it scratches more easily. For example:

Unlike diamonds, CZ’s scratch and become dull and lifeless over the long term.

Jeweler site

Cubic zirconium — Mass-produced since 1976, cubic zirconium scratches easily [...].

Business Insider - 5 ways to spot a fake diamond

Now it is true that CZ is softer than diamond (8 on the Mohs hardness scale vs 10 for diamond) - however that is still harder than most other everyday substances (Quartz has 7, glass has 5.5, steel 4-7, tungsten 7.5), so it seems unlikely to scratch in everyday use.

Is it true that CZ jewelry will scratch noticeably faster in everyday use than diamonds?

  • 4
    I wonder if other hardness 8 gemstones are similarly considered inferior because of scratching in everyday use: emerald, topaz, amethyst... – GEdgar Sep 19 '17 at 14:43
  • @GEdgar: Good point. This could also indicate that the lower hardness is not a problem in practice. – sleske Sep 20 '17 at 7:09
  • 2
    @GEdgar Emeralds are considered to scratch easily, and they are similar hardness. But in gemology, how easily it scratches is not only related to hardness, but also impurity. Some precious stones are more desired with impurity because they bring the color. – fredsbend Sep 21 '17 at 0:47
  • @fredsbend: Sorry, I can't follow. What does scratching have to do with impurity? Or do you mean "desirability is not only related to hardness, but also impurity"? – sleske Oct 17 '17 at 7:49
  • @sleske Impurity type and amount can affect hardness and stability of individual gems. Hardness numbers you see are averages. Desirability is a different issue and at least half subjective. General rules about desirability and value do include assessment of the impurities, but not too much on hardness. – fredsbend Oct 17 '17 at 15:21

You must log in to answer this question.

Browse other questions tagged .