Mineral phase
- IMA name
- Microcline
- Secondary names
- Amazonstone
- Class
- silicate mineral
- Compound type
- tektosilicate
- Comments
- Low temperature dimorph of Orthoclase
- Formula
- $KAlSi_3O_8$
- Chemical formula
- KAlSi3O8
- Elemental formula
- K Al Si3 O8
- Isotope mixture type
- terrestrial abundance
- Composition comments
- Common replacements: Na, Ca - Common impurities: Fe, Li, Cs, Rb, H2O, Pb
- Oxides
-
Formula $K_{2}O$ $Na_{2}O$ $CaO$ $Al_{2}O_{3}$ $SiO_{2}$ Mass fraction (%) 16.92 18.32 64.76
Strunz
- Class
- silicates (09)
- Division
- tektosilicate without zeolitic H2O (09.F)
- Family
- without additional non-tetrahedral anions, (Al,B):Si = 1:1 (09.FA)
- Code
- 09.FA.30
Dana
- Major class
- silicates (VIII)
- Class
- tectosilicate Al-Si framework (76)
- Type
- with Al-Si frameworks (76.01)
- Group
- K (Na,Ba) feldspars (76.01.01)
- Code
- 76.01.01.05
- Phase type
- crystalline
- Crystal system
- triclinic
- Crystal class
- pinacoidal
- Crystal class symbol
- -1 (Ci)
- Crystal spacegroup
- P-1
- Molar mass
- 278.33 $g/mol$
- Density
- 2.56 $g/cm^3$
- State NTP
- solid
- Refringence type
- biaxial
- Refringence sign
- negative
- Birefringence
- 0.007 - 0.010
- Refraction index $n_{\alpha}$
- 1.514 - 1.529
- Refraction index $n_{\beta}$
- 1.518 - 1.533
- Refraction index $n_{\gamma}$
- 1.521 - 1.539
- Dispersion V
- relatively weak (r > v)
- Pure color
- white
- Color
- gray, grayish yellow, yellowish, bluish green, green, salmon-pink
- Diaphaneity
- transparent to translucent
- Luster
- vitreous