metamorphic
Greenstone (likely serpentinite)
Serpentinite; mainly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chlorite, or other altered minerals
AI-generated identification · may be incorrectTypically dark green to gray-green, waxy to subvitreous luster, massive rather than visibly crystalline, Mohs hardness about 2.5–4, and specific gravity roughly 2.5–2.6. The image is insufficient for definitive identification; similar appearance can occur in altered basalt or chlorite schist.
Identified More metamorphic →
Explore Greenstone (likely serpentinite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically dark green to gray-green, waxy to subvitreous luster, massive rather than visibly crystalline, Mohs hardness about 2.5–4, and specific gravity roughly 2.5–2.6. The image is insufficient for definitive identification; similar appearance can occur in altered basalt or chlorite schist.
Formation & geological history
Forms when ultramafic mantle rocks such as peridotite are hydrated during metamorphism, commonly in oceanic crust and subduction zones. Formation ages vary widely, from Precambrian to modern tectonic settings.
Uses & applications
Used as decorative stone, carvings, countertops, and lapidary material; historically used for tools and ornaments. Most small rough specimens have modest commercial value.
Geological facts
Serpentinite often contains slick, fibrous, or mottled textures and may show black magnetite grains. Some varieties can contain asbestos-form minerals, so avoid cutting or generating dust unless composition is confirmed.
Field identification & locations
Look for a green waxy surface, low hardness, massive texture, and possible dark veining; a steel nail may scratch it. Common in California, Italy, New Zealand, Canada, and ophiolite belts worldwide.
More like this
