Thermal Shock

This property refers to how easy it is for a stone to be damaged by a quick change in temperature. Some of the commonly used gems that can be affected by thermal shock include Apatite, Opal, bi-color Tourmaline, and tri-color Tourmaline. Apatite and multi-colored tourmaline are very heat sensitive. I have seen them fracture when going from room temperature to very hot water from the faucet. Many other jewelers and I have found out the hard way that putting opals under intense light for extended periods of time is not a good idea. It can cause them to fracture. I have also heard of people fracturing their opals when they washed their hands in hot water after wearing them outside on a cold winter’s day. Stones affected by this kind of fracturing cannot be repaired.

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