Druzy quartz geode
Microcrystalline quartz (SiO₂), commonly lining a volcanic geode cavity
mineral
Category
Mineral, Possibly Rock Fragment Containing A Mineral
Browse mineral, possibly rock fragment containing a mineral specimens identified by the Rock Identifier community.
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Porphyry (Rhyolite / Andesite Porphyry Pebble)
Porphyritic Igneous Rock
igneous
Quartz Geode fragment
Crystalline Silicon Dioxide (SiO2)
mineral
Bull Quartz with Mica and Host Rock
Massive Quartz (SiO2) with Muscovite/Chlorite inclusions
igneous
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic extrusive volcanic rock with secondary mineral infilling)
igneous
Milky quartz (rough quartz specimen)
Quartz, silicon dioxide (SiO₂)
mineral
Agate (or Banded Agate)
Agate (a variety of Chalcedony, which is a cryptocrystalline form of Quartz); Chemical Formula: SiO₂ (Silicon Dioxide)
Mineral, specifically a Cryptocrystalline Quartz variety
Quartz Geode Fragment
Crystalline Silicon Dioxide (SiO2)
mineral
Shale
Argillaceous sedimentary rock
sedimentary
Shale
Shale (Lutite)
sedimentary
Likely weathered iron-rich stone
Uncertain; possibly limonite/goethite-bearing rock
mineral
Garnet Gneiss
Gneiss containing almandine-pyrope garnet
metamorphic
Laterite (iron-rich nodule, possibly Bauxite as a subtype)
Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)
Sedimentary
Garnet in Schist (Mica Schist with Garnet Inclusion)
Garnetiferous Mica Schist (X3Al2(SiO4)3)
metamorphic
Pebble / Rounded Rock
Lithic fragment / Water-worn rock
sedimentary
Turquoise
Turquoise - CuAl6(PO4)4(OH)8·4H2O
mineral
Greenstone / altered mafic rock
Likely chlorite–actinolite schist or metabasalt; exact identification requires testing
metamorphic
Weathered quartz-bearing rock, possibly granite or gneiss
Indeterminate; likely quartz–feldspar–mica aggregate, possibly granitic gneiss
igneous
Porphyritic Basalt
Porphyritic Basalt (containing Plagioclase phenocrysts)
igneous
Likely galena-bearing ore specimen
Galena (PbS), possibly with quartz or calcite gangue
mineral
Basalt
Mafic extrusive igneous rock
igneous
Fossilized oyster or bivalve shell
Fossil Gryphaeidae or Ostreoidea; calcitic shell, CaCO₃
fossil
Fragmented Sedimentary Pebble
Clastic Sedimentary Specimen
sedimentary
Garnet-bearing Quartzite
Metamorphic rock containing Almandine Garnet (Fe3Al2(SiO4)3) and Quartz (SiO2)
metamorphic
Mica Schist
Muscovite/Biotite Schist
metamorphic
Sandstone
Arenite
sedimentary
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
mineral
Greenstone, likely serpentinite
Serpentinite; predominantly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with chlorite, talc, magnetite, or antigorite
metamorphic
Pebble
Lithic fragment / Rounded rock fragment
sedimentary
Quartz (Chert/Chalcedony variety)
Silicon Dioxide (SiO2)
mineral
Green Opal (Prase Opal)
SiO2 · nH2O (Hydrated Silicon Dioxide)
mineral
Schist
Mica Schist
metamorphic
Gravel or Crushed Stone
Fragmented Aggregate Stone
sedimentary or igneous fragment
Tumbled or cut iron-rich mineral specimen
Likely limonite/goethite (hydrated iron oxides), possibly weathered hematite
mineral
Weathered quartz-rich granitoid (likely granite or granodiorite)
Granite–granodiorite; chiefly quartz (SiO₂), feldspar, and minor mica/amphibole
igneous
Limonitic Sandstone with Inclusion
Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt containing Zeolite and Calcite inclusions
igneous
Possible fossilized ammonite or concretion
Indeterminate fossil specimen; possibly an ammonoid mold/cast in iron-rich sedimentary rock
fossil
Weathered basalt or mafic volcanic rock
Basalt; primarily plagioclase feldspar, pyroxene, and possibly olivine
igneous
Quartz Druzy (Geode Fragment)
Silicon Dioxide (SiO2)
mineral
Shale
Shale (Consolidated fine-grained clay/silt)
sedimentary
Likely weathered mica schist fragment
Mica schist, chiefly muscovite/biotite mica with quartz and feldspar
metamorphic