Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
mineral
Category
Sedimentary (Chemically Precipitated) Or Metamorphic
Browse sedimentary (chemically precipitated) or metamorphic specimens identified by the Rock Identifier community.
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Optical Calcite
Calcium Carbonate (CaCO3)
mineral
Flint
SiO2 (Microcrystalline Quartz)
sedimentary
Specularite (Specular Hematite)
Iron Oxide (Fe2O3)
mineral
Amethyst Geode
Amethyst/Purple Quartz (SiO2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Honey Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Honey calcite (likely calcitic limestone or marble)
Calcite — CaCO₃; possibly calcite-rich limestone/marble
mineral
Iron-rich metamorphic rock (likely banded iron formation fragment)
Banded iron formation; chiefly quartz (SiO₂) and iron oxides such as hematite (Fe₂O₃) and magnetite (Fe₃O₄)
metamorphic
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Sandstone Cobble with Liesegang Rings
Arenite with iron oxide precipitation (SiO2 matrix with Fe2O3 banding)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Flint Nodule with Chalk Cortex
Chert (Microcrystalline Quartz) SiO2
sedimentary
Fossiliferous Limestone
Biogenic Limestone (CaCO3)
sedimentary
Banded iron formation fragment (ironstone)
Banded iron formation; chiefly hematite/magnetite with chert (SiO₂)
sedimentary
Weathered limestone pebble
Limestone; predominantly calcite (CaCO₃)
sedimentary
Orange calcite
Calcite (calcium carbonate, CaCO₃)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Calcite crystal cluster
Calcite — calcium carbonate, CaCO₃
mineral
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Weathered iron-rich rock, possibly limonite-bearing sandstone
Limonite/goethite-bearing sandstone or ferruginous conglomeratic rock
sedimentary
Yellow Quartzite (River Pebble)
Metamorphic Quartzite (SiO2)
metamorphic
Quartz with Host Rock
Silicon Dioxide (SiO2)
mineral
Quartz (Clear or Milky)
Silicon Dioxide (SiO2)
mineral
Milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz Vein in Matrix (Breccia / Host Rock with Quartz)
Silicon Dioxide (SiO2) in Host Rock Matrix
metamorphic
Graphite
Graphite (Chemical Formula: C)
Mineral (Native Element)
Quartz
Silicon Dioxide (SiO2)
mineral
Iron-stained quartz vein rock
Quartz-rich vein material, predominantly SiO₂, with iron oxyhydroxides (goethite/limonite) and likely sulfide alteration
metamorphic
Quartz (Iron-stained or Chalcedony varieties)
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Raw yellow calcite
Calcite, calcium carbonate (CaCO₃)
mineral
Hematite
Hematite (Iron(III) oxide, Fe2O3)
mineral
Quartz-rich rock, likely milky quartz or quartzite
Quartz (SiO₂); possibly quartzite with iron-oxide staining
metamorphic
Likely weathered quartz or quartz-rich pebble
Quartz, silicon dioxide (SiO₂)
mineral
Iron-Stained Quartzite
Quartzite (chemically SiO2 with Fe2O3/FeO(OH) staining)
metamorphic