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Al2O3
(gcide) | Sapphire \Sap"phire\ (? or ?; 277), n. [OE. saphir, F. saphir,
L. sapphirus, Gr. ?, of Oriental origin; cf. Heb.
sapp[imac]r.]
1. (Min.) Native alumina or aluminium sesquioxide, Al2O3;
corundum; esp., the blue transparent variety of corundum,
highly prized as a gem.
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Of rubies, sapphires, and of pearl['e]s white.
--Chaucer.
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Note: Sapphire occurs in hexagonal crystals and also in
granular and massive forms. The name sapphire is
usually restricted to the blue crystals, while the
bright red crystals are called Oriental rubies (see
under Ruby), the amethystine variety Oriental
amethyst (see under Amethyst), and the dull massive
varieties corundum (a name which is also used as a
general term to include all varieties). See Corundum.
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2. The color of the gem; bright blue.
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3. (Zool.) Any humming bird of the genus Hylocharis, native
of South America. The throat and breast are usually bright
blue.
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Star sapphire, or Asteriated sapphire (Min.), a kind of
sapphire which exhibits asterism.
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Al2O3
(gcide) | Sesquioxide \Ses`qui*ox"ide\, n. [Sesqui- + oxide.] (Chem.)
An oxide containing three atoms of oxygen with two atoms (or
radicals) of some other substance; thus, alumina, Al2O3 is
a sesquioxide.
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Al2O3
(gcide) | Alumina \A*lu"mi*na\, n. [L. alumen, aluminis. See Alum.]
(Chem.)
One of the earths, consisting of two parts of aluminium and
three of oxygen, Al2O3.
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Note: It is the oxide of the metal aluminium, the base of
aluminous salts, a constituent of a large part of the
earthy siliceous minerals, as the feldspars, micas,
scapolites, etc., and the characterizing ingredient of
common clay, in which it exists as an impure silicate
with water, resulting from the decomposition of other
aluminous minerals. In its natural state, it is the
mineral corundum.
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Al2O3
(gcide) | Corundum \Co*run"dum\ (k[-o]*r[u^]n"d[u^]m), n.; pl. Corundums
(k[-o]*r[u^]n"d[u^]mz). [Also corindon.] [From Hind. kurand
corundum stone.] (Min.)
The mineral alumina (Al2O3), as found native in a
crystalline state. Transparent varieties are used as
gemstones, including sapphire, which is the fine blue
variety; the oriental ruby, or red sapphire; the {oriental
amethyst}, or purple sapphire; and adamantine spar, the
hair-brown variety. It is the hardest substance found native,
next to the diamond.
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Note: The name corundum is sometimes restricted to the
non-transparent or coarser kinds. Emery is a
dark-colored granular variety, usually admixed with
magnetic iron ore.
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