Serpentinite facoid |
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 SerpentiniteGreen serpentinite (greenschist metamorphic facies), derived from an ultramafic host rock (possibly mantle rock or a protolith of volcanic or intrusive igneous rock). This is a sample of a serpentinite “facoid”- a naturally polished watermelon seed-shaped rock displaying plastic-like flow-texture pattern on it surface. This sample came from the San Andreas fault zone near San Jose, California. |
| https://gotbooks.miracosta.edu/rocks/metamorphic/22.html | 2/2/2021 |