Mineral - Scorodite
Scorodite
Chemical Properties
Mineral Class
Arsenates
Toxicity
middle
Formula
Fe³⁺[AsO₄]·2H₂O
Unit Cell
a=8.95 b=10.32 c=10.04 Z=8
Physical Properties
Hardness
3.5 - 4
Streak
white
Density
Normal (2-3,5)
Cleavage
Imperfect after {201}
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
greenbluevioletcolorless
Birefringence
0.036
Luster
Vitreous,
Adamantine
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-dipyramidal - 2/m 2/m 2/m
Space Group
Pbca (61)
Habit
dipyramidal, massive, prismatic
Formation
(1) As a secondary mineral formed by the aqueous oxidation of arsenic-bearing sulfides (particularly arsenopyrite) under near-surface, acidic oxidation conditions in the weathering zone of supergene ore deposits
Paragenesis
Twinning
Rarity
Very rare
Synonyms
Scorodite
Composition
Elements
Mass
As₂O₅
49.79
Fe₂O₃
34.60
H₂O
15.61
Japan (Palache et al. 1952)
Groups and Members
Variscite-Group