metamorphic
Serpentine (likely polished/tumbled)
Serpentinite; chiefly antigorite, lizardite, and/or chrysotile Mg₃Si₂O₅(OH)₄
AI-generated identification · may be incorrectOpaque pale green with darker green mottling and a waxy luster, consistent with serpentine. Mohs hardness is about 2.5–4; it commonly has a fine-grained, massive texture and no obvious cleavage. Exact identification would benefit from a hardness or streak test.
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Physical properties
Opaque pale green with darker green mottling and a waxy luster, consistent with serpentine. Mohs hardness is about 2.5–4; it commonly has a fine-grained, massive texture and no obvious cleavage. Exact identification would benefit from a hardness or streak test.
Formation & geological history
Forms when ultramafic mantle rocks such as peridotite hydrate during low-temperature metamorphism. Serpentinite is common in accreted oceanic-rock belts of the Pacific Northwest, including areas around the San Juan Islands; ages vary widely, commonly Mesozoic.
Uses & applications
Used as ornamental stone, carvings, beads, and tumbled specimens; massive serpentinite has limited architectural use. This small polished piece is mainly collectible or decorative.
Geological facts
Its green color comes from serpentine-group minerals, sometimes mixed with magnetite, carbonate, or chromite. It can resemble jade, but serpentine is generally softer and less dense.
Field identification & locations
An excellent regional match for Anacortes. Test cautiously: it should scratch with a steel knife more readily than jade, while quartz will not scratch it; avoid generating dust because some serpentinite can contain fibrous chrysotile asbestos.
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