Rock Identifier

Category

Organic Crystal (Mineraloid)

Browse organic crystal (mineraloid) specimens identified by the Rock Identifier community.

Graphite-rich schist (likely graphite ore) (Graphite-bearing schist; predominantly graphitic carbon (C) with mica, quartz, and possible feldspar) — metamorphic

Graphite-rich schist (likely graphite ore)

Graphite-bearing schist; predominantly graphitic carbon (C) with mica, quartz, and possible feldspar

Fossilized Coral (Rugosa / Scleractinia (Agatized or Calcitized Coral)) — fossil

Fossilized Coral

Rugosa / Scleractinia (Agatized or Calcitized Coral)

Chert (Grey/Black variety) (Chert (Silicon Dioxide, SiO2)) — sedimentary

Chert (Grey/Black variety)

Chert (Silicon Dioxide, SiO2)

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

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Black Chert) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper/Black Chert)

Silicon Dioxide (SiO2)

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

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (specifically Flint or Jasper variant) (Microcrystalline quartz (SiO2)) — sedimentary

Chert (specifically Flint or Jasper variant)

Microcrystalline quartz (SiO2)

Chert (specifically Jasper/Agate variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Amber (Rough) (Amber (Fossilized Tree Resin, succinite)) — mineral

Amber (Rough)

Amber (Fossilized Tree Resin, succinite)

Tahitian Pearl (Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3) — mineral

Tahitian Pearl

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Petrified Wood (Silicified wood (Quartz/Chalcedony replacement)) — fossil

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement)

Green Chert (Microcrystalline Quartz (SiO2)) — sedimentary

Green Chert

Microcrystalline Quartz (SiO2)

Chert / Flint (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Chert (vuggy variety) (Microcrystalline silica (SiO2)) — sedimentary

Chert (vuggy variety)

Microcrystalline silica (SiO2)

Chert (Nodule) (Chert (primarily Microcrystalline Quartz - SiO2)) — sedimentary

Chert (Nodule)

Chert (primarily Microcrystalline Quartz - SiO2)

Sandstone (with carbonaceous plant fragments) (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone (with carbonaceous plant fragments)

Arenite (composed primarily of SiO2)

Chert (specifically River Stone / Jasper variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (specifically River Stone / Jasper variety)

Microcrystalline Quartz (SiO2)

Chert (Nodule/Pebble) (Chert (Silicon Dioxide, SiO2)) — sedimentary

Chert (Nodule/Pebble)

Chert (Silicon Dioxide, SiO2)

Petrified Wood (Silicified Paleoxylon (SiO2)) — fossil

Petrified Wood

Silicified Paleoxylon (SiO2)

Moqui Marble (Shaman Stone) (Iron Oxide Concretion (composed primarily of Quartz sand with Hematite/Goethite shell)) — sedimentary

Moqui Marble (Shaman Stone)

Iron Oxide Concretion (composed primarily of Quartz sand with Hematite/Goethite shell)

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

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Picasso Jasper (or Picasso Marble) (Metamorphosed Limestone (Calcium Carbonate, CaCO3, with impurities)) — metamorphic

Picasso Jasper (or Picasso Marble)

Metamorphosed Limestone (Calcium Carbonate, CaCO3, with impurities)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Pink Opal (Common Opal) (Amorphous Hydrated Silica (SiO2·nH2O)) — mineral

Pink Opal (Common Opal)

Amorphous Hydrated Silica (SiO2·nH2O)

Petrified Wood (Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)) — metamorphic

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)

Red Jasper (Microcrystalline Quartz (Chalcedony), SiO2) — sedimentary

Red Jasper

Microcrystalline Quartz (Chalcedony), SiO2

Chert (often called Flint in this context) (Silicon Dioxide (SiO2)) — sedimentary

Chert (often called Flint in this context)

Silicon Dioxide (SiO2)

Chert (Jasper/Limonitic Chert) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper/Limonitic Chert)

Microcrystalline Quartz (SiO2)

Chert (Jasper-rich) (Microcrystalline/Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper-rich)

Microcrystalline/Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (includes Flint & Jasper) (Chert (Siliceous sedimentary rock, chemical formula SiO2)) — sedimentary

Chert (includes Flint & Jasper)

Chert (Siliceous sedimentary rock, chemical formula SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Zebra Jasper (Opaque microcrystalline Quartz (SiO2) with impurities) — sedimentary

Zebra Jasper

Opaque microcrystalline Quartz (SiO2) with impurities

Chert / Flint (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Chert (Tan/Buff Chert) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Tan/Buff Chert)

Microcrystalline Quartz (SiO2)

Chert (Chocolate or Brown Flint) (Chert (SiO2)) — sedimentary

Chert (Chocolate or Brown Flint)

Chert (SiO2)

Sandstone Concretion (Clastic sedimentary rock (primarily Quartz SiO2)) — sedimentary

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Chert (Flint) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Iron-stained) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Iron-stained)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2 - Silicon Dioxide)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Chert with Quartz/Calcite Vein (Microcrystalline Silica (SiO2)) — sedimentary

Chert with Quartz/Calcite Vein

Microcrystalline Silica (SiO2)