All About the Properties of Euclase, Sphene, and Phenacite

EUCLASE.

Euclase is very brittle, and therefore is rarely used as an ornamental stone.

This mineral has the hardness of 7.5; specific gravity, 3.I; lustre, vitreous to pearly; it is transparent to semi-transparent, doubly refractive, is not acted upon by acids, fuses under the blow-pipe to a white enamel, and is composed of:

Silica 41.2

Alumina 35.2

Glucina 17.4

Water 6.2

Euclase occurs in Brazil, in the neighborhood of Villa Rica, and also in the Urals, in colorless, pale green, blue, pale yellow, and white colors.

SPHENE.

Sphene or titanite is also a brittle mineral, 5 to 5.5 in hardness; specific gravity, 3.4 to 3.56; transparent, doubly refractive; lustre, adamantine to resinous; colors, brown, gray, yellow, green, black, and colorless; and composition:

Silica 31

Titanium oxide 41

Lime 27

Ferrous oxide 1

When transparent in colorless, greenish, or yellow colors, this mineral presents an appearance like the fire opal.

Sphene is found in Switzerland, the Urals, Tyrol, Finland, Wales, Ireland, Germany, Canada, and the United States.

PHENACITE.

This mineral, rarely used as a gem stone, is 7.5 to 8 in hardness; specific gravity, 2.96 to 3; lustre, vitreous; transparent to semi-translucent, doubly refractive, it does not melt before the blow-pipe, and contains:

Silica 54.2

Glucina 45.8

Phenacite occurs colorless, and also bright wine-yellow inclining to red, and brown. This stone is found in Russia, Mexico, and Alsace.