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Webster 1913 Edition

Topaz

To′paz

,
Noun.
[OE.
topas
, F.
topaze
, L.
topazos
, or
topazion
, a kind of precious stone, Gr.
τόπαζος
,
τοπάζιον
; possibly akin to Skr.
tap
to glow (cf.
Tepid
). According to some, the name is from
Topazos
, a small island in the Red Sea, where the Romans obtained a stone which they called by this name, but which is the chrysolite of the moderns.]
1.
(Min.)
A mineral occurring in rhombic prisms, generally yellowish and pellucid, also colorless, and of greenesh, bluish, or brownish shades. It sometimes occurs massive and opaque. It is a fluosilicate of alumina, and is used as a gem.
2.
(Zool.)
Either one of two species of large, brilliantly colored humming birds of the genus
Topaza
(
Topaza pella
or
Topaza pyra
), of South America and the West Indies.
☞ The two tail feathers next to the central ones are much longer that the rest, curved, and crossed. The Throat is metallic yellowish-green, with a tint like topaz in the center, the belly is bright crimson, the back bright red. Called also
topaz hummer
.
False topaz
.
(Min.)
See the Note under
Quartz
.

Webster 1828 Edition

Topaz

TO'PAZ

,
Noun.
[Gr.] A mineral, said to be so called from Topazos, a small isle in the Arabic gulf, where the Romans obtained a stone which they called by this name, but which is the chrysolite of the moderns. The topaz is of a yellowish color. It sometimes occurs in masses, but more generally crystallized in rectangular octahedrons. Topaz is valued as a gem or precious stone, and is used in jewelry. It consists of silex, fluoric acid and alumin, in the following proportions; alumin 57 parts, silex 34, and fluoric acid 7 or 8.
Of topaz there are three subspecies, common topaz, shorlite and physalite.

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