Chemical Formula: (K,Ba)[Al(Si,Al)Si2O8]
Locality: Imfield, Switzerland.
Name Origin: From the Greek hyalos – “glass” and phanos – “to appear.”
Hyalophane or jaloallofane is a crystalline mineral, part of the feldspar group of tectosilicates. It is considered a barium-rich potassium feldspar. Its chemical formula is (K,Ba)[Al(Si,Al)Si2O8], and it has a hardness of 6 – 6½. The name hyalophane comes from the Greek hyalos, meaning “glass”, and phanos meaning “to appear”.
An occurrence of hyalophane was discovered in 1855 in Lengenbach Quarry, Imfield, in the municipality of Binn, Switzerland. The mineral is found predominantly in Europe, with occurrences in Switzerland, Australia, Bosnia, Germany, Japan, New Jersey, and the west coast of North America.
Physical Properties
Cleavage: {001} Perfect, {010} Imperfect
Color: Colorless, Yellow, White, Red.
Density: 2.81
Diaphaneity: Transparent to translucent
Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals.
Hardness: 6-6.5 – Orthoclase-Pyrite
Luminescence: Non-fluorescent.
Luster: Vitreous (Glassy)
Magnetism: Nonmagnetic
Streak: white
Photos:
[Al(Si,Al)Si2O8] Locality: Imfield, Switzerland. Name Origin: From the Greek hyalos - "glass" and phanos - "to appear." Hyalophane){kind=link}