why do opals crack so often?

Home Frequently Asked Questions (FAQ) Glass why do opals crack so often?....

Opals are not a perfect 33 COE.  Therefor sometimes they can crack in glass, even years later.  This is why Elev8 Premier rarely uses them, and if they do, it goes on a piece that can come off, if it were to crack.

But they are always used because we love the sparkle!