metamorphic
Waterworn greenstone pebble
Likely serpentinite or chlorite-rich metamorphic rock; exact identification requires testing
AI-generated identification · may be incorrectHardness typically 3–6 Mohs; olive-green, brown, and reddish mottling; wet vitreous-to-waxy luster; massive, fine-grained texture with no visible cleavage. Rounded shape and glossy surface result from stream abrasion.
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Physical properties
Hardness typically 3–6 Mohs; olive-green, brown, and reddish mottling; wet vitreous-to-waxy luster; massive, fine-grained texture with no visible cleavage. Rounded shape and glossy surface result from stream abrasion.
Formation & geological history
Probably formed by low- to moderate-grade metamorphism or hydrothermal alteration of ultramafic rock, potentially millions to billions of years ago, then transported and polished in a stream. The image alone cannot establish its geological age or exact composition.
Uses & applications
Suitable mainly as a decorative pebble, lapidary/tumbled stone, or collector specimen; serpentinite may be carved, while harder greenstones can be used for ornaments and minor construction aggregate.
Geological facts
Green coloration commonly comes from serpentine, chlorite, or epidote minerals; reddish-brown areas may reflect iron oxides. A streak, hardness, specific-gravity, and acid test would distinguish serpentinite from jasper, basalt, or altered schist.
Field identification & locations
Look for a smooth stream-worn form, mottled green color, waxy sheen, and low-to-moderate density; common in rivers draining ultramafic or metamorphic terrains. Avoid assuming jade from color alone—jade is notably tougher and typically harder.
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