mineral
Feldspar (Orthoclase)
Potassium Feldspar (KAlSi3O8)
Hardness: 6 on Mohs scale; Color: Pink, salmon, or orange-beige; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.55–2.63
- Hardness
- 6 on Mohs scale
- Color
- Pink, salmon, or orange-beige
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 6 on Mohs scale; Color: Pink, salmon, or orange-beige; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.55–2.63
Formation & geological history
Formed primarily in igneous rocks like granite and pegmatites, as well as some metamorphic rocks, through the cooling of magma or hydrothermal activity. It is one of the most abundant minerals in the Earth's crust.
Uses & applications
Used in the manufacture of glass and ceramics (porcelain), as a filler in paints and plastics, and occasionally as a gemstone (such as moonstone).
Geological facts
Feldspar makes up about 41% of the Earth's continental crust by weight. The name is derived from the German 'Feldspat', meaning 'field spar'.
Field identification & locations
Identify by its blocky shape and pinkish color. It is harder than glass but can be scratched by quartz. Common in granitic terrains worldwide.
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sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
Metamorphic Rock