metamorphic
Polished gray-white stone, likely serpentinized marble or soapstone
Uncertain; probable serpentinite-bearing carbonate rock, chiefly calcite/dolomite with serpentine and dark accessory minerals
AI-generated identification · may be incorrectMohs hardness about 2.5–5, depending on composition; rounded and polished, pale gray to cream with dark green-black veining and mottling, with a waxy to dull luster. The granular/interlocking texture and lack of visible crystals suggest a fine-grained metamorphic aggregate.
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Physical properties
Mohs hardness about 2.5–5, depending on composition; rounded and polished, pale gray to cream with dark green-black veining and mottling, with a waxy to dull luster. The granular/interlocking texture and lack of visible crystals suggest a fine-grained metamorphic aggregate.
Formation & geological history
Likely formed by metamorphism and hydrothermal alteration of ultramafic or carbonate-rich rock; age depends on locality and cannot be determined visually. Commonly occurs in metamorphic belts and serpentinite zones.
Uses & applications
Used as a decorative or tumbled stone, carving material, and occasionally for ornamental tiles; collector value is generally modest unless provenance or unusual patterning is known.
Geological facts
The dark material may be serpentine, magnetite, amphibole, or other alteration minerals. The surface appears human-polished, so texture and hardness tests are more reliable than appearance alone.
Field identification & locations
Common sources include California, Vermont, Italy, China, and New Zealand. A steel nail can test hardness, while dilute hydrochloric acid may fizz if exposed carbonate is present; identification requires testing or laboratory analysis.
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