Formula: (Cu,Al)2H2Si2O5(OH)4 . nH2O
Origin of name: From Greek for gold and glue
Crystal system: Orthorhombic
Crystal class: Unknown
Twinning:
Unit cell: a = 5.8 Ǻ, b = 17.8 Ǻ, c = 8.1 Ǻ
Colour: Shades of blue, blue-green, green
Diaphaneity:
Luster: Vitreous, earthy
Habit: Crystals microscopic, acicular, in radiating groups or aggregates; cryptocrystalline; opal-like; earthy; botryoidal; crystal
Hardness: 2 to 4
Specific gravity: 2.01 to 2.4
Cleavage: None
Tenacity: Conchoidal to uneven; brittle
Streak: White
Synonyms/varieties: Demidovite, Bisbeeite
Comments:
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