A semi-precious gemstone with a speckled, multi-colored iridescent quality. Looking at an opal in different light or at different angles produces a rainbow-like effect of multiple colors. Opal is 5.5-6.5 on Mohs' scale of hardness. Primary sources include Australia, Brazil, Guatemala, Honduras, Indonesia, Japan, Mexico, Russia, Nevada, and Idaho.
Jewelry Glossary
Opal
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