Remember Porcellanite
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Porcellanite Technical Terms
Porcellanite: A dense, siliceous rock formed as a indurated or baked clay or shale with a dull, light-colored, cherty appearance, often found in the roof or floor of a burned-out coal seam. GG
Porcellanite: A dense, siliceous rock formed as a indurated or baked clay or shale with a dull, light-colored, cherty appearance, often found in the roof or floor of a burned-out coal seam. GG