metamorphic
Weathered greenstone pebble (probable serpentinite or altered basalt)
Serpentinite-group rock, commonly dominated by antigorite/lizardite; identification is uncertain from the photograph
AI-generated identification · may be incorrectPale green-gray, fine-grained, dull to slightly waxy luster, rounded by erosion, and lacking visible crystals or cleavage; typical hardness is about 2.5–4 Mohs, with variable density. Brown patches likely represent iron-oxide weathering.
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Physical properties
Pale green-gray, fine-grained, dull to slightly waxy luster, rounded by erosion, and lacking visible crystals or cleavage; typical hardness is about 2.5–4 Mohs, with variable density. Brown patches likely represent iron-oxide weathering.
Formation & geological history
Likely formed by hydrothermal alteration of ultramafic rock (serpentinite) or mafic volcanic rock, then exposed and rounded in a stream or shoreline environment; age cannot be determined visually.
Uses & applications
Commonly used as crushed stone, decorative facing, carving material, and landscaping stone; this small weathered specimen has mainly educational or modest collector value.
Geological facts
Serpentinite often develops green colors from hydration of olivine- and pyroxene-rich mantle rocks and may contain magnetite, producing dark specks or magnetic response.
Field identification & locations
Look for a smooth green waxy surface, very fine texture, iron staining, and possible weak magnetism; common in tectonically active mountain belts and ophiolite complexes. A hardness test, streak test, magnet, and thin-section or XRF analysis would improve identification.
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