RocksdayMicrocline
Microcline is a mineral (KAlSi₃O₈) with a Mohs hardness of 6–6.5 and a vitreous to pearly luster, usually pink, white, green or gray.
The common potassium feldspar of granite pegmatites. Green microcline is amazonite. By eye it looks like orthoclase.
How to identify microcline
- Blocky pink, white or green crystals with two cleavages near 90°.
- Hardness about 6 — scratches glass with difficulty.
- Green pieces are amazonite. Pink and white ones cannot be separated from orthoclase without a microscope.
Often confused with
OrthoclaseOrthoclase is the monoclinic potassium feldspar; the grid twinning of microcline shows only under crossed polarizers.
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Where it's found
- Pegmatites in Colorado
- Minas Gerais, Brazil
- Norway
- Madagascar
Uses
Ceramics and, as amazonite, gemstones.
Rock tumbling
Great for tumbling.
Did you know?
A lot of pink 'orthoclase' in pegmatites is microcline. The difference is the crystal structure, not the color.
Microcline FAQ
What is microcline?
Microcline is a mineral (KAlSi₃O₈) with a Mohs hardness of 6–6.5 and a vitreous to pearly luster, usually pink, white, green or gray. The common potassium feldspar of granite pegmatites. Green microcline is amazonite. By eye it looks like orthoclase.
How do you identify microcline?
Blocky pink, white or green crystals with two cleavages near 90°. Hardness about 6 — scratches glass with difficulty. Green pieces are amazonite. Pink and white ones cannot be separated from orthoclase without a microscope.
How hard is microcline?
Microcline has a Mohs hardness of 6–6.5. Microcline scratches glass, and a steel knife can't scratch it.
Where is microcline found?
Notable localities include Pegmatites in Colorado; Minas Gerais, Brazil; Norway; and Madagascar.
What is microcline used for?
Ceramics and, as amazonite, gemstones.
Can you tumble microcline?
Yes — it tumbles well.
What is microcline often confused with?
Microcline is most often confused with Orthoclase, Amazonite and Albite. Orthoclase is the monoclinic potassium feldspar; the grid twinning of microcline shows only under crossed polarizers. Amazonite is the green variety of microcline. Albite is the sodium feldspar, usually whiter, with fine striations.
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