Formula: Cu5Zn3(TeO4)4(OH)8 7H2O
Origin of name: after its locality, The Centennial Eureka mine, 1 mile southeast of Eureka, Tintic District, Juab County, Utah, USA.
Crystal system: Triclinic
Crystal class: 1 or 1
Twinning:
Unit cell: a = 8.794, b = 9.996, c = 5.66, α = 104.1°, β = 90.07°, γ = 96.34°
Colour: Blue, blue-green, pale blue
Diaphaneity: Translucent
Luster: Vitreous to pearly, adamantine
Habit: Prismatic to thin tabular to bladed crystals, elongated along [001], showing {010} and {001}, in parallel to subparallel aggregates, to 0.6 mm, also as sheaves and bow tie-like groups
Hardness: 4.5
Specific gravity: 5.33
Cleavage: None
Tenacity: Brittle, uneven fracture
Streak: Pale blue
Synonyms/varieties:
Comments:
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