TOPAZ
Topaz is superficially similar to quartz. Topaz
is an aluminum hydroxy-fluorosilicate (Al2SiO4(F,OH)2).
It is very hard (H≡8), has a nonmetallic, glassy luster, and often occurs
in ~columnar crystals having striations parallel to the long axis. Topaz
varies in color from clearish to yellowish to greenish to bluish to pinkish,
etc. Unlike quartz, topaz has one good cleavage. Topaz is an
igneous mineral; it is found in many pegmatites.
Topaz
- peachy-colored crystals ranging in length from 9 to 16 mm.
Topaz
from Teofilo Otoni, Minas Gerais State, Brazil.
(Wayne State University collection, Detroit, Michigan,
USA)
Topaz
("imperial topaz") from Ouro Preto, Minas Gerais State, Brazil.
Specimen owned by Carolyn Machester.
Topaz
(bluish-green) & albite feldspar (white) from Taqueral, Brazil.
Specimen owned by Carolyn Machester.
Topaz
from the Katlang Mountains, Pakistan.
Specimen owned by Carolyn Machester.
Topaz
(dark peachy-orange) & albite feldspar (white) from Dassu, Baltistan,
Pakistan.
Specimen owned by Carolyn Machester.
Topaz
(upper right) & quartz (clearish crystals at left & lower left) from
Sakangyi, Mogok, Burma.
Specimen owned by Carolyn Machester.