Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Category
Browse organic (biological specimen) specimens identified by the Rock Identifier community.
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Graphite
Graphite (Carbon, C)
Agatized fossil fragment, possibly silicified coral
Chalcedony (microcrystalline SiO₂) replacing carbonate fossil material
Coralline Algae / Maerl
Lithothamnion (Biogenic Calcium Carbonate)
Amber
Succinite (Organic Gemstone)
Lichen-covered granite or granitic gneiss
Granite: quartz + feldspar + mica; possibly gneiss if foliation is confirmed
Chert (Arrowhead Artifact)
Microcrystalline Quartz (SiO2)
Chert Arrowhead
Cryptocrystalline Quartz (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Chert / Jasper
Silicon Dioxide (SiO2)
Chert (Jasper/Flint variety)
Silicon dioxide (SiO2) - Microcrystalline Quartz
Fossilized Brachiopod
Phylum Brachiopoda (replaced by Calcite/CaCO3)
Fossiliferous Limestone
Fossiliferous Limestone
Fossiliferous Limestone
Carbonate Rock (CaCO3 with organic inclusions)
Weathered granitic/concrete-looking boulder (likely granite or granodiorite)
Granite–granodiorite; chiefly quartz, feldspar, and mica
Amber
Fossilized tree resin (not a true mineral as it is organic and amorphous); Chemical formula is highly variable, but often approximated as C10H16O.
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline silica (SiO2)
Chert or Flint
Silicon dioxide (SiO2)
Chert (Green and Black Jasper variant)
Cryptocrystalline Quartz (SiO2)
Ironstone concretion / Limonitic Sandstone
Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)
Chert (River Pebble)
Silicon Dioxide (SiO2)
Fossil coral fragment
Likely colonial scleractinian coral; calcite/aragonite (CaCO₃)
Jasper with Agate and Quartz Inclusions
Silicon Dioxide (SiO2) - Chalcedony / Quartz aggregate
Weathered iron-rich sandstone or ferruginous pebble
Quartz-rich sandstone with iron-oxide cement; exact identification requires testing
Chert / River Pebble
Silicon Dioxide (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (often called Jasper or River Pebble)
Microcrystalline Quartz (SiO2)
Amber
Succinite
Chert (Jasper variety)
Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Cryptocrystalline Quartz (SiO2)
Chert (Common Opal/Jasper transition)
Silicon Dioxide (SiO2)
Orange Calcite (Iron-Stained)
Calcium Carbonate (CaCO3)
Crushed Limestone
Calcium Carbonate (CaCO3)
Black Onyx and Mother of Pearl
Cryptocrystalline Quartz (SiO2) and Nacre (Calcium Carbonate)
Chert
Chert (SiO₂)
Chert (River Pebble)
Chert (Cryptocrystalline Quartz, SiO₂)
Chert / Jasper
Silicon Dioxide (SiO2)
Chert (Jasper variety)
Microcrystalline Quartz (SiO2)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Chert (Field Stone)
Chert (Silicon Dioxide, SiO2)
Chert Arrowhead
Microcrystalline Quartz (SiO2)