The Collaborative International Dictionary
Opal \O"pal\, n. [L. opalus: cf. Gr. ?, Skr. upala a rock, stone, precious stone: cf. F. opale.] (Min.) 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.
Wiktionary
n. Any transparent to translucent opal with a warm body colour of yellow, orange, or red.
WordNet
n. an opal with flaming orange and yellow and red colors [syn: girasol]
Usage examples of "fire opal".
He had the ring ready in a leather box lined with crimson velvet, a fire opal the size of a pigeon's egg set in a complicated circle of dark antique gold.
Unlike the other gems this was a fire opal, a far more precious kind.
I was dreaming of a great jewel, a fire opal filled with crimson flame.
Around her neck, suspended by a golden chain, hung a red fire opal.