Pink Orthoclase Feldspar with Dendrites

Physical Properties

Hardness: 6 on Mohs scale; Color: Salmon pink to flesh-colored; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific gravity: 2.56-2.58.

Formation & Geological History

Formed in igneous environments, primarily as a major constituent of granite and pegmatites. The dark 'tree-like' patterns are manganese oxide dendrites that crystallized later through mineral-rich water seeping into cracks.

Uses & Applications

Industrial use in the manufacture of glass, ceramics, and enamels. Common in mineral collections and occasionally as a decorative stone in masonry.

Geological Facts

The name Orthoclase comes from the Greek 'orthos' (straight) and 'klasis' (fracture), referring to its two cleavage planes at right angles. The dendrites are often mistaken for fossilized plants, but they are purely inorganic crystal growths.

Field Identification & Locations

Identify by its distinct pink color, 90-degree cleavage, and hardness (can scratch glass but is scratched by quartz). Commonly found in the Rocky Mountains and the Appalachian range in the USA.

Identified on: 4/14/2026

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