Hypertext Webster Gateway: "opal"
From Webster's Revised Unabridged Dictionary (1913) (web1913)
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.
From WordNet (r) 1.7 (wn)
opal
n : a translucent mineral consisting of hydrated silica of
variable color; some varieties are used as gemstones
Additional Hypertext Webster Gateway Lookup
Gateway by dict@stokkie.net
stock only wrote the gateway and does not have any control over the contents;
see the Webster Gateway FAQ,
and also the Back-end/database links and credits.