The Collaborative International Dictionary of English v.0.48:
Garnet \Gar"net\, n. [OE. gernet, grenat, OF. grenet,grenat, F.
grenat, LL. granatus, fr. L. granatum pomegranate, granatus
having many grains or seeds, fr. granum grain, seed. So
called from its resemblance in color and shape to the grains
or seeds of the pomegranate. See Grain, and cf. Grenade,
A mineral having many varieties differing in color and in
their constituents, but with the same crystallization
(isometric), and conforming to the same general chemical
formula. The commonest color is red, the luster is vitreous,
and the hardness greater than that of quartz. The
dodecahedron and trapezohedron are the common forms.
Note: There are also white, green, yellow, brown, and black
varieties. The garnet is a silicate, the bases being
aluminia lime (grossularite, essonite, or cinnamon
stone), or aluminia magnesia (pyrope), or aluminia iron
(almandine), or aluminia manganese (spessartite), or
iron lime (common garnet, melanite, allochroite), or
chromium lime (ouvarovite, color emerald green). The
transparent red varieties are used as gems. The garnet
was, in part, the carbuncle of the ancients. Garnet is
a very common mineral in gneiss and mica slate.
Garnet berry (Bot.), the red currant; -- so called from its
transparent red color.
Garnet brown (Chem.), an artificial dyestuff, produced as
an explosive brown crystalline substance with a green or
golden luster. It consists of the potassium salt of a
complex cyanogen derivative of picric acid.