Crinoid Stem Fossil
Crinoid ossicle (phylum Echinodermata)
fossil
Category
Sedimentary (Silicified Fossiliferous Chalcedony)
Browse sedimentary (silicified fossiliferous chalcedony) specimens identified by the Rock Identifier community.
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Carnelian (Agate)
SiO2 (Silicon Dioxide with Iron Oxide inclusions)
mineral
Gemstone Tree Brooch (Agate and Quartz)
Silicon Dioxide (SiO2)
mineral
Green Chalcedony (Batu Akik)
Silicon Dioxide (SiO2)
gemstone
White Chalcedony
Silicon Dioxide (SiO2)
mineral
Blue Chalcedony
Cryptocrystalline Quartz (SiO2)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Chalcedony (Agate/Carnelian)
Cryptocrystalline Quartz (SiO2)
mineral
Fossilized shell or brachiopod
Likely a calcareous brachiopod or bivalve fossil; exact identification requires clearer detail and scale
fossil
Druzy Chalcedony (Agate Geode)
Silica (SiO2) - Cryptocrystalline Quartz with druzy macrocrystalline quartz
mineral
Carnelian
SiO2 (Variety of Chalcedony)
gemstone
Agate
Banded Chalcedony (SiO2)
mineral
Quartz (Chalcedony/Agate)
Silicon Dioxide (SiO2)
mineral
Geode half
Geode (often quartz/chalcedony based)
sedimentary or igneous
Chert / Jasper
Silicon Dioxide (SiO2)
sedimentary
Carnelian (Polished Beads)
SiO2 (Silicon Dioxide - Microcrystalline Quartz)
gemstone
Fossiliferous Limestone (Crinoid stem fragments)
Bioclast-bearing Carbonate Rock (Caco3)
fossil
Purple Chalcedony
Silicon Dioxide (SiO2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Chalcedony (Quartz)
Silicon Dioxide (SiO2)
mineral
Jasper
Silicon dioxide (SiO2)
Sedimentary / Mineral
Fossiliferous Limestone Pebble
Calcite-rich Fossiliferous Marine Limestone
fossil
Red Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
sedimentary
Tumbled gray-green pebble, likely chert or altered volcanic rock
Cryptocrystalline quartz (chert), possibly silicified volcanic material
sedimentary
Jasper and Basalt (Lake Superior Agate or Jasper Pebble)
Silicified rock / Cryptocrystalline quartz (SiO2) with basalt matrix
sedimentary
Biggs Jasper (Picture Jasper)
Silicon Dioxide (SiO2) - Opaque Silicified Volcanic Ash
sedimentary
Wonderstone (Liesegang Sandstone)
Silicified Sandstone with Liesegang Rings (SiO2 + FeO(OH))
sedimentary
Red Jasper (Quartz)
Silicon Dioxide (SiO2) with Iron impurities
sedimentary
Chert / Chalcedony Nodule
Silicon Dioxide (SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Chert
Microcrystalline quartz (SiO2)
sedimentary
Dalmatian Jasper
Peralkaline rhyolite with arfvedsonite inclusions
igneous
Dendritic Agate
Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with hematite inclusions
sedimentary
Dyed Chalcedony (Agate)
Silicon Dioxide (SiO2) with artificial pigment
mineral
Orthoceras Fossil in Limestone
Orthoceras (extinct genus of cephalopods), mineralized as Calcite (CaCO3) in Fossiliferous Limestone
sedimentary
Tumbled brecciated jasper
Silica-rich microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions
mineral
Crinoid Stem Fossil
Crinoida (columnal ossicles)
fossil
Jasper
Cryptocrystalline quartz (SiO2)
Sedimentary/Mineral
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Mineral (or mineraloid if microcrystalline)
Red Chalcedony (likely dyed)
Chalcedony (a variety of Quartz), SiO2
Mineral (Cryptocrystalline Quartz)
Weathered limestone
Calcite-rich carbonate rock (mostly CaCO₃), possibly fossiliferous limestone
sedimentary