Mineral - Smithsonite
Smithsonite
Chemical Properties
Mineral Class
Carbonates
Toxicity
none
Formula
Zn[CO₃]
Unit Cell
a=4.65 c=15.03 Z=6
Physical Properties
Hardness
4 - 4.5
Streak
white
Density
Heavy (3,5-6)
Cleavage
Perfect after {10 1 1}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
yellowgreenbluepinkcolorless
Birefringence
0.227
Luster
Vitreous,
Pearly
Transparency
translucent,
transparent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
trigonal
Point Group
ditrigonal-scalenohedral - 3 m
Space Group
R 3 c (167)
Habit
coarse, bulbous, massive, kidney-shaped, Rhombohedron, Scalenohedron, spear-shaped, stalactitic, prismatic, grape-shaped
Formation
Secondary, resulting from the supergene oxidation of primary zinc sulfides (sphalerite) in the oxidation zone of ore deposits, whereby dissolved zinc ions react with carbonate-bearing solutions or the host rock.
Paragenesis
Twinning
Rarity
Common
Synonyms
Smithsonite
Composition
Elements
Mass
CO₂
35.25
ZnO
64.55
MgO
0.04
CaO
0.35
Germany (Palache et al. 1952)
Groups and Members
Calcite-Group