Mineral - Anthophyllite
Anthophyllite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
(Mg,Fe²⁺)₂(Mg,Fe²⁺)₅Si₈O₂₂(OH)₂
Unit Cell
a=18.54 b=18.03 c=5.28 Z=4
Physical Properties
Hardness
5.5 - 6
Streak
whitegraygray white
Density
Normal (2-3,5)
Cleavage
Perfect after {210}, angles at 54.5° and 125.5°, distinct after {010} and {100}
Fracture
conchoidal
Tenacity
Elastic-flexible,
Brittle
Optical Properties
Color
whitebrowngray
Birefringence
0.023
Luster
Vitreous
Transparency
translucent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-dipyramidal - 2/m 2/m 2/m
Space Group
Pnma (62)
Habit
fibrous, prismatic, radial
Formation
Through medium to high-grade metamorphism (schists, amphibolites, gneisses, granulites) from clayey protoliths
Magmatic in ultramafic and mafic rocks
Paragenesis
Twinning
Rarity
Common
Synonyms
Anthophyllite
Composition
Elements
Mass
SiO₂
58.08
TiO₂
0.04
Al₂O₃
0.30
Fe₂O₃
0.65
FeO
10.18
MnO
0.20
MgO
27.99
CaO
0.17
Na₂O
0.05
K₂O
0.01
H₂O
2.20
Austria (Dana 1892)
Groups and Members
Amphibole-Supergroup
Mg-Fe-Mn-Amphibole-Group
Anthophyllite (Ath) Amphibole-Subgroup
Name and first discovery : Named by Schumacher in 1801 after the Latin word "anthophyllum" for "carnation" due to its brownish color.
Chemistry : Dimorph after cummingtonite
Synonyms : asbestos, anthogrammite, anthophylline, antofillite
Varieties : Kupfferite
Abbreviation : Ath
literature
Dana, J. D., & Dana, E. S. (1892). The system of mineralogy of James Dwight Dana, 1837-1868: descriptive mineralogy . J. Wiley & sons.