mineral
Likely polished bronzite or serpentine-rich rock
Probable bronzite, an iron-bearing orthopyroxene (Mg,Fe)SiO₃; exact identification requires testing
AI-generated identification · may be incorrectBrown to olive-gold, mottled, and strongly vitreous to greasy with reflective cleavage surfaces; bronzite hardness is about 5–6 Mohs, orthorhombic, with two good cleavage directions and specific gravity near 3.3–3.5.
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Physical properties
Brown to olive-gold, mottled, and strongly vitreous to greasy with reflective cleavage surfaces; bronzite hardness is about 5–6 Mohs, orthorhombic, with two good cleavage directions and specific gravity near 3.3–3.5.
Formation & geological history
Bronzite forms in magnesium- and iron-rich igneous or metamorphic rocks through crystallization or alteration at depth; its age depends on the host rock, commonly Paleozoic or older in commercial material.
Uses & applications
Used as a decorative stone, tumbled specimen, cabochon, and ornamental carving material; it has limited industrial use compared with pyroxene-rich rocks.
Geological facts
The bronze-like shimmer is produced by fine intergrowths and cleavage reflections, often called schiller. Similar appearance can occur in serpentine, brown mica, or weathered peridotite.
Field identification & locations
Look for bronze chatoyancy, moderate hardness, and cleavage; a steel knife may scratch some serpentine but generally struggles against bronzite. Common sources include India, Austria, Italy, South Africa, and the United States.
