Fossilized Brachiopod or Gastropod in Chert/Limestone
Phylum Brachiopoda / Mollusca
fossil
Category
Synthetic (Not A Rock Or Mineral)
Browse synthetic (not a rock or mineral) specimens identified by the Rock Identifier community.
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Quartz in Matrix (Lepidolite or Quartzite)
Silicon Dioxide (SiO2) with host rock
mineral
Porphyritic Basalt (with Pyrolusite or Iron-oxide staining)
Porphyritic Basalt (Mafic Extrusive)
igneous
Sandstone (Picture Sandstone)
Arenite (primarily SiO2)
sedimentary
Quartz Geode Segment
Crystalline Silicon Dioxide (SiO2)
mineral
Gneiss (Banded Gneiss Cobble)
Gneiss
metamorphic
Druzy Quartz Geode (Oco or Moroccan variety)
Silicon Dioxide (SiO2)
mineral
Aura Quartz (Anomalously Coated Quartz)
Silicon Dioxide (SiO2) treated with vaporized metals
mineral
Gneiss (with Quartzite and Biotite)
Gneiss containing SiO2 (Quartz), K(Mg,Fe)3AlSi3O10(OH)2 (Biotite), and (K,Na,Ca)AlSi3O8 (Feldspar)
metamorphic
Sandstone
Arenite (primary component SiO2)
sedimentary
Quartz cluster, possibly druzy quartz on matrix
Quartz (SiO₂), likely microcrystalline to coarse crystalline; associated matrix uncertain
mineral
Sandstone
Clastic Sedimentary Rock
sedimentary
Quartz and Iron Oxide
Quartz (Silicon Dioxide, SiO2) with possible Limonite/Hematite inclusions
mineral
Sandstone
Sedimentary Rock (Quartz Arenite)
sedimentary
Granite
Felsic intrusive igneous rock
igneous
Gneiss
Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)
metamorphic
Sandstone
Quartz Arenite / Sedimentary Rock
sedimentary
Granite
Granite (Felsic Plutonic Rock)
igneous
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
igneous
Chalcopyrite
Copper Iron Sulfide (CuFeS2)
mineral
Amygdaloidal Basalt
Amygdaloidal Mafic Volcanic Rock
igneous
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (SiO2 based typically)
sedimentary
Hag Stone (Adder Stone / Geode-bearing Pebble)
Sedimentary Rock with Cavity (often Quartzite, Limestone, or Sandstone)
sedimentary
Sandstone
Arenite (SiO2 principal)
sedimentary
Dark Igneous Rock (Likely Basalt or Diabase)
Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.
Igneous
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Quartz Vein in Metamorphic Rock
Quartz-veined Schist or Gneiss
metamorphic
Gneiss
High-grade Metamorphic Gneiss
metamorphic
Quartz Geode
Silicon dioxide (SiO2)
sedimentary
River Stone (likely Basalt or Greywacke)
Basalt with mineral veining
igneous
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary
Mica-rich metamorphic rock, likely schist
Muscovite–biotite schist, possibly with quartz and feldspar
metamorphic
Banded Serpentine
Serpentine group (subgroup Lizardite or Antigorite) - Mg3Si2O5(OH)4
metamorphic
Greenstone
Metabasalt (Greenstone)
metamorphic
River Pebble (likely Quartzite or Chert)
Sedimentary Clast (Silicon Dioxide dominant)
sedimentary
Banded Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Green Apophyllite and Stilbite on Quartz Cluster
Apophyllite-(K) (KCa4(Si8O20)(F,OH)·8H2O), Stilbite-Ca (NaCa4(Si27Al9)O72·28H2O), Quartz (SiO2)
Mineral
Fluorite with Quartz coating
Calcium Fluoride (CaF2) with Silicon Dioxide (SiO2)
mineral
Banded mica schist
Mica schist, chiefly muscovite/biotite with quartz and feldspar
metamorphic