Constituent
- Name
- Augite
- IMA name
- Augite
- Class
- silicate mineral
- Compound type
- inosilicate
- Comments
-
generaly crystalline
The full Ca, ordered Orthopyroxene equivalent of Augite is the Diopside-Hedenbergite series
- Relevance
- main - major
- Arrangement
- single phase
- Mass fraction
- 1.0 0.001
- Formula
- Chemical formula
- (Ca,Mg,Fe2+)2(Si,Al)2O6
- Elemental formula
- (Ca)0.64-0.9 Na0 (Mg)1.02-1.5 (Fe2+)0.34-1.5 (Fe3+)0 Ti0 Al0 Si2 O6
- Isotope mixture type
- terrestrial abundance
- Composition comments
- relatively low in calcium with some disorder of occupancies of Fe2+ and Mg in both octahedral sites - Common substitution: Na, Al, , Ti (also disordered) - Common impurities: Cr, Mn, Zn, K - from "Electron microprobe analysis shows that Pyroxenes lie in the Augite field ()"; Allen et al. 1998 - Assume no Na, , Ti and Al replacement
- Oxides
-
Formula Mass fraction (%) 16.2 11.0 18.6 54.2 - Oxides comments
- For - calculated with elemental formula
Strunz
- Class
- silicates (09)
- Division
- inosilicate (09.D)
- Family
- with 2-periodic single chains, Si2O6; pyroxene family (09.DA)
- Code
- 09.DA.15
Dana
- Major class
- silicates (VIII)
- Class
- inosilicate single-width unbranched chains, w=1 (65)
- Type
- with chains P=2 (65.01)
- Group
- C2/c clinopyroxenes (Ca clinopyroxenes) (65.01.03a)
- Code
- 65.01.03a.03
- Phase type
- crystalline
- Crystal system
- monoclinic
- Crystal class
- prismatic
- Crystal class symbol
- 2/m (C2h)
- Crystal spacegroup
- C2/c
- Texture
- polycrystalline
- Molar mass
- 221.6
- Density
- 3.2
- Refringence type
- biaxial
- Refringence sign
- positive
- Birefringence
- 0.026
- Refraction index
- 1.680 - 1.735
- Refraction index
- 1.684 - 1.741
- Refraction index
- 1.706 - 1.774
- Dispersion V
- weak to distinct (r > v)
- Color
- green, brown green, light brown, purplish brown, dark brown, black
- Diaphaneity
- translucent to opaque
- Luster
- vitreous