Rock Identifier

Category

Sedimentary (Formed From Silica Deposits)

Browse sedimentary (formed from silica deposits) specimens identified by the Rock Identifier community.

Sandstone (Arenite (primarily SiO2 with various cementing agents)) — sedimentary

Sandstone

Arenite (primarily SiO2 with various cementing agents)

Banded Calcite (often sold as Mexican Onyx) (Calcium Carbonate (CaCO3)) — sedimentary

Banded Calcite (often sold as Mexican Onyx)

Calcium Carbonate (CaCO3)

Dendritic Agate (Silicon Dioxide with Manganese/Iron oxide inclusions (SiO2)) — mineral

Dendritic Agate

Silicon Dioxide with Manganese/Iron oxide inclusions (SiO2)

Black Opal (Hydrated Silica (SiO2·nH2O)) — mineral

Black Opal

Hydrated Silica (SiO2·nH2O)

Pink Chalcedony (Silicon Dioxide (SiO2)) — mineral

Pink Chalcedony

Silicon Dioxide (SiO2)

Amethyst (Amethyst (Silicon Dioxide, SiO2)) — mineral

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartzite River Rock (Quartzite (primarily SiO2)) — metamorphic

Quartzite River Rock

Quartzite (primarily SiO2)

Milky Quartz with Chlorite/Mica inclusions (Silicon Dioxide (SiO2) with inclusions) — mineral

Milky Quartz with Chlorite/Mica inclusions

Silicon Dioxide (SiO2) with inclusions

Quartz (White/Milky with Iron Staining) (Silicon Dioxide (SiO2)) — mineral

Quartz (White/Milky with Iron Staining)

Silicon Dioxide (SiO2)

Celestite Geode (Celestine (Strontium Sulfate, SrSO4)) — mineral

Celestite Geode

Celestine (Strontium Sulfate, SrSO4)

Milky Quartz (Water-worn Pebble) (Silicon Dioxide (SiO2)) — mineral

Milky Quartz (Water-worn Pebble)

Silicon Dioxide (SiO2)

Amethyst Geode (Silicon Dioxide (SiO2) with iron impurities) — mineral

Amethyst Geode

Silicon Dioxide (SiO2) with iron impurities

Chert (Jasper variety) (Microcrystalline quartz (SiO2)) — sedimentary

Chert (Jasper variety)

Microcrystalline quartz (SiO2)

Chert (specifically Pink/Tan Chert) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Pink/Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Calcite (Calcite (CaCO3)) — mineral

Calcite

Calcite (CaCO3)

Chrysocolla (Hydrated copper phyllosilicate, Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)) — mineral

Chrysocolla

Hydrated copper phyllosilicate, Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)

Fluorite (Calcium Fluoride (CaF2)) — mineral

Fluorite

Calcium Fluoride (CaF2)

Quartz (Vein Quartz) (Silicon Dioxide (SiO2)) — mineral

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Grey Jasper (Tumbled Quartz variant) (Jasper (Silicon Dioxide, SiO2)) — sedimentary

Grey Jasper (Tumbled Quartz variant)

Jasper (Silicon Dioxide, SiO2)

Banded Gneiss (Gneiss (High-grade Metamorphic Rock)) — metamorphic

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Chalcedony (Moonstone-like Agate) (Silicon Dioxide (SiO₂)) — mineral

Chalcedony (Moonstone-like Agate)

Silicon Dioxide (SiO₂)

Quartz Pebble (Quartz (Silicon Dioxide, SiO2)) — mineral

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Iron-Stained Quartz Pebble) (Silicon Dioxide (SiO2)) — mineral

Quartz (Iron-Stained Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz Pebble (Silicon Dioxide (SiO2)) — sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (River Pebble) (Silicon Dioxide (SiO2)) — mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

River Cobble (likely Quartzite or Chert) (Quartzite (SiO2)) — metamorphic

River Cobble (likely Quartzite or Chert)

Quartzite (SiO2)

Chalcedony (Yellow Agate/Chert) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (Yellow Agate/Chert)

Silicon Dioxide (SiO2)

Chert (variations include Flint/Jasper) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (variations include Flint/Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fossil Coral (Rugose Coral) (Rugosa (extinct order); typically composed of Calcite (CaCO3) or replaced by Quartz (SiO2)) — sedimentary

Fossil Coral (Rugose Coral)

Rugosa (extinct order); typically composed of Calcite (CaCO3) or replaced by Quartz (SiO2)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Banded Agate (Cryptocrystalline Quartz (SiO2)) — mineral

Banded Agate

Cryptocrystalline Quartz (SiO2)

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Common Opal (Hydrated amorphous form of silica (SiO2·nH2O)) — mineral

Common Opal

Hydrated amorphous form of silica (SiO2·nH2O)

Chalcedony (Desert Rose or Botryoidal Chalcedony) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (Desert Rose or Botryoidal Chalcedony)

Silicon Dioxide (SiO2)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Rough Precious Opal (Hydrated Silica (SiO2·nH2O)) — mineral

Rough Precious Opal

Hydrated Silica (SiO2·nH2O)

Granite (Plutonic felsic igneous rock) — igneous

Granite

Plutonic felsic igneous rock

Amethyst (Quartz (SiO2) variety) — Mineral

Amethyst

Quartz (SiO2) variety

Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz Pebble (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)