Spongolite
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Spongolite is a sediment or sedimentary rock composed principally of the remains of largely articulated fossils of rigid-bodied siliceous sponges. In contrast, spiculite is either sediment or sediment
Spongolite texture, click to enlarge (2MB)
Chert
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Chert is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide. Chert is characteristically of biological origin, but may
Spongolite
…this type of spongolite include ceramics, refractory products, chromato-graphic supplies and catalysis matrices. In Europe and Australia, spiculitic chert (silica-cemented spiculite), called spongolite by archaeologists, was locally used by prehistoric cultures to fashion stone tools and other artifacts…
A hand sized sample of chert
Chert (dark bands) in the Devonian Corriganville-New Creek limestone, Everett, Pennsylvania
Folded beds of chert comprising the Late Permian to Jurassic-aged Liminangcong Formation at Busuanga, Palawan, Philippines
Chert nodule within soft limestone at Akçakoca, Turkey