mineral

Microcline Feldspar

KAlSi3O8

Hardness of 6 on the Mohs scale. Colors range from white, cream, yellow, to pink or green (Amazonite). Luster is vitreous to pearly. Crystal system is triclinic, often showing distinctive twinning. Good cleavage in two directions at nearly right angles.

Identified July 28, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in felsic igneous rocks like granite and pegmatites through the slow cooling of magma, as well as in metamorphic environments.

Uses & applications

Widely used in the manufacture of ceramics, porcelain, glass, and as a gemstone or ornamental carving material.

Geological facts

Microcline is the most common potassium feldspar. When it contains lead impurities and has a bright green color, it is known as Amazonite. It commonly exhibits perthitic texture, which is an intergrowth of two different feldspars.

Field identification & locations

Identified in the field by its blocky crystal habit, near-right angle cleavage, and distinct grid-like twinning pattern (often visible under magnification). Found worldwide in pegmatite-rich regions.