Euclase
Euclase is very brittle, and therefore is rarely used as an ornamental stone.
This mineral has the hardness of 7.5; specific gravity, 3.1; 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.