The Encyclopedia · Stones & materials
Opal
A gem that shows flashes of spectral colour, called play-of-colour.
Australian opal, mined from the 1870s, transformed opal jewelry. Art Nouveau jewelers such as René Lalique loved it, and it remained popular through the twentieth century.
What to look for
Opal contains water and can crack or craze when it dries out or meets sudden changes in temperature. Many opals are doublets or triplets, a thin slice of opal backed with another material; look at the side of the stone.
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