metamorphic
Serpentine-rich pebble
Serpentinite; chiefly serpentine-group minerals (chrysotile, lizardite, antigorite), commonly with magnetite and minor olivine/pyroxene
AI-generated identification · may be incorrectTypically pale green to yellow-green with mottled or waxy appearance; Mohs hardness about 2.5–4, vitreous to greasy luster, generally massive rather than visibly crystalline, and no consistent cleavage. The rounded form indicates natural abrasion or tumbling; the photograph alone cannot confirm the identification.
Identified More metamorphic →
Explore Serpentine-rich pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically pale green to yellow-green with mottled or waxy appearance; Mohs hardness about 2.5–4, vitreous to greasy luster, generally massive rather than visibly crystalline, and no consistent cleavage. The rounded form indicates natural abrasion or tumbling; the photograph alone cannot confirm the identification.
Formation & geological history
Forms when ultramafic rocks such as peridotite undergo low-temperature hydration and metamorphism, commonly in oceanic crust and tectonic mélange zones. Serpentinization is mainly Mesozoic to Cenozoic in exposed examples, though rocks of many ages occur.
Uses & applications
Used as decorative stone, carvings, countertops, and historically as a low-grade ornamental “marble”; some varieties are collected. Fibrous chrysotile-bearing material should not be cut or abraded because its dust can be hazardous.
Geological facts
Green color and waxy texture are characteristic, but similar-looking materials include chlorite-rich rocks, weathered basalt, and slag. A streak, hardness, magnetism, and specific-gravity test would improve identification.
Field identification & locations
Common in ophiolites and mountain belts, including California, Italy, New Zealand, and the Appalachians. Look for greasy green surfaces, black magnetite specks, relatively low hardness, and occasional weak magnetism.
More like this
