Metachert jasper |
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 Metachert (jasper)Jasper (a variety of red chert) with quartz-filled fractures. Metachert rock like this is common in the lower Franciscan Formation (Jurassic) in the central Coastal California region. This sample is a stream cobble from Tres Pinos Creek area, San Benito County, CA. |
| https://gotbooks.miracosta.edu/rocks/metamorphic/12.html | 2/2/2021 |