Fossiliferous Limestone
Bioclastic Limestone (CaCO3)
sedimentary
Category
Mineralogical Specimen
Browse mineralogical specimen specimens identified by the Rock Identifier community.
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Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Botryoidal Chalcedony (Agate)
Silicon Dioxide (SiO2)
mineral
Blue Obsidian (Cullet Glass)
Silicon Dioxide (Amorphous Glass)
mineral
Porphyritic volcanic rock, likely andesite or rhyolite
Porphyritic andesite–rhyolite; chiefly plagioclase, quartz, and altered ferromagnesian minerals in a fine groundmass
igneous
Muscovite Schist
Metamorphic rock primarily composed of quartz and muscovite mica
metamorphic
Blue Obsidian
Volcanic Glass (SiO2 with inclusions)
igneous
Unidentified weathered mineral/rock fragment
Indeterminate; likely a weathered iron-rich silicate or sulfide-bearing specimen
mineral
Quartzite Pebble
Quartzite (SiO2)
metamorphic
Quartz (Chert/Chalcedony variety)
Silicon Dioxide (SiO2)
sedimentary
Polished Agate Geode
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Limonite-stained Chert/Jasper
Microcrystalline Quartz (SiO2) with Iron Oxides (FeO(OH)·nH2O)
sedimentary
Jasper (Green Jasper/Heliotropic Chert)
Silicon Dioxide (SiO₂)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
sedimentary
Granite (with Beryl/Aquamarine)
Granite (Feldspar, Quartz, Mica, and Beryl Be3Al2Si6O18)
igneous
Quartz on Sandstone
Silicon Dioxide (SiO2) in Lithic Sandstone
sedimentary
Conglomerate
Conglomeratic Sandstone
sedimentary
Granite with Tourmaline or Biotite
Phaneritic Igneous Rock (Granoid)
igneous
Banded Sandstone
Quartz Arenite (with iron oxide banding)
sedimentary
Porphyritic Andesite
Andesite (Porphyritic texture)
igneous
Quartz Geode with Goethite/Hematite
Silicon Dioxide (SiO2) with Iron Oxides
mineral
Smoky Quartz (Herkimer-style)
Silicon Dioxide (SiO2)
mineral
Agate
Chalcedony (Microcrystalline Quartz) - SiO2
Mineral
Iron-rich breccia or weathered limonite-bearing rock
Goethite–limonite ironstone, possibly ferruginous breccia
sedimentary
Copper Ore (Malachite, Azurite, and Chalcopyrite in Host Rock)
Copper-bearing polymetallic mineral aggregate (Cu-minerals)
mineral
Probable weathered granite or granitic gneiss
Granite/granitic gneiss; mainly quartz, feldspar, and mica
igneous
Geode with Quartz and Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Peacock Ore
Bornite (Cu5FeS4) with surface tarnish
mineral
Granite
Granite (composed mainly of Quartz, Potassium Feldspar, Plagioclase, and Biotite/Mica)
igneous
Chalcedony with Quartz
Silicon Dioxide (SiO2)
mineral
Quartz with Mica (likely Muscovite)
Silicon Dioxide (SiO2) with Potassium Aluminum Silicate Hydroxide Fluoride
igneous/metamorphic
Tiger's Eye (Tumbled Blue/Black-Golden variety)
Pseudomorph of Quartz after Crocidolite (SiO2 with Iron inclusions)
metamorphic
Slate with Fossiliferous Impressions
Metamorphosed Argillaceous Rock (Fossiliferous Slate)
metamorphic
Chert (or Chalcedony) Nodule
Microcrystalline Quartz (SiO2)
sedimentary
Blue-gray mineral specimen (possibly sodalite)
Undetermined; appearance may be consistent with sodalite (Na₈Al₆Si₆O₂₄Cl₂), but the image is insufficient for reliable identification
mineral
Silicified fossil-bearing chert
Microcrystalline quartz (SiO₂), likely chalcedony replacing carbonate shell material
fossil
Weathered granitic rock
Granite, likely biotite-bearing granite or granodiorite
igneous
Quartz-rich vein rock, possibly milky quartz with iron-oxide staining
Quartz (SiO₂), likely with limonite/goethite and minor host-rock material
mineral
Quartz Pebble with Muscovite Mica
Quartz (SiO2) with Muscovite Mica (KAl2(AlSi3O10)(F,OH)2)
sedimentary
Schist (Micaceous Schist)
Mica Schist
metamorphic
Clear Quartz
Silicon Dioxide (SiO2)
mineral