Many kinds of gemstones frequently receive treatments or enhancements to improve their appearance or stability. With the demand for attractive, affordable opals growing, vendors are finding new ways to treat lower-quality opals to improve their salability, too. Treated opals can be quite beautiful, but problems arise when unscrupulous or uninformed sellers don’t disclose these treatments.[toc]
Identify Your Opal Variety
What are Hydrophane Opals?
When considering opal treatments, hydrophane opals are your biggest concern. This type of opal is porous, which means it’s susceptible to all sorts of procedures that simply wouldn’t work on other types.
If you suspect your opal has undergone treatment, you should test it to see if it’s a hydrophane. To do this, look at your gem through a loupe in transmitted light. (A flashlight shining through the stone will do just fine). Next, place a drop of water on the stone’s surface. A non-porous opal will appear the same after the drop evaporates, but a hydrophane opal will absorb the drop. If you can see the…