opal

1. n. A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity. Source: opted

2. n. a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones Source: wordnet

3. A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity. Note: The precious opal presents a peculiar play of colors of delicate tints, and is highly esteemed as a gem. One kind, with a varied play of color in a reddish ground, is called the harlequin opal. The fire opal has colors like the red and yellow of flame. Common opal has a milky appearance. Menilite is a brown impure variety, occurring in concretions at Menilmontant, near Paris. Other varieties are cacholong, girasol, hyalite, and geyserite. Source: webster

4. A mineral consisting, like quartz, of silica, but inferior toquartz in hardness and specific gravity. Source: adambom

5. n:100 n. a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones Source: ecdict

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