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Ignimbrite is a volcanic rock consisting mainly of pumice fragments, formed by the consolidation of material deposited by pyroclastic flows
From Latin ignis fire + imber, imbr- shower of rain, storm cloud + -ite
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
From Cornish gossen from gos, blood from Old Cornish guit
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock