Biotite-rich schist (mica schist)
Mica schist, chiefly biotite (K(Mg,Fe)₃AlSi₃O₁₀(OH,F)₂), with possible quartz and feldspar
metamorphic
Category
Sedimentary Or Igneous (Host Environment)
Browse sedimentary or igneous (host environment) specimens identified by the Rock Identifier community.
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Weathered schist or gneiss
Quartz–feldspar–mica metamorphic rock
metamorphic
Gneiss
Gneissic Metamorphic Rock
metamorphic
White quartz fragment
Quartz (silicon dioxide, SiO₂)
mineral
Milky Quartz (or Vein Quartz)
Silicon Dioxide (SiO2)
mineral
Clear Quartz Crystal
Silicon Dioxide (SiO2)
mineral
Chalcedony (Agate/Carnelian precursor)
Chalcedony (Silicon Dioxide, SiO2)
mineral
Quartz Vein / Quartz Matrix
Silicon Dioxide (SiO2)
mineral
Sapphire
Corundum (Al2O3)
mineral
Quartz-encrusted Matrix
Silicon Dioxide (SiO2) with Ferruginous Sandstone
sedimentary
Weathered schist or gneiss cobble
Foliated silicate rock, likely mica schist or biotite gneiss
metamorphic
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) with host rock (often Schist or Basalt)
mineral
Pyrite in Matrix
Iron Sulfide (FeS2) embedded in host rock
mineral
Shale
Argillite / Shale
sedimentary
Oyster shell fragment
Ostreidae shell; primarily calcite (CaCO₃)
fossil
Weathered sandstone or arkosic sandstone
Clastic sandstone, likely quartz–feldspar-rich (arkose)
sedimentary
Magnetite
Magnetite (Fe3O4)
mineral
Mica-rich schist
Muscovite–quartz schist (tentative; image alone cannot confirm mineral composition)
metamorphic
Chert / Jasper
Silicon Dioxide (SiO2)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Quartz (specifically Clear Quartz or Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Red Garnet (likely Almandine or Pyrope)
Garnet group: X3Y2(SiO4)3 (e.g., Almandine: Fe3Al2Si3O12)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Banded Chert in Matrix
Microcrystalline Quartz (SiO2)
sedimentary
Quartz (Milky/Smoky variety on matrix)
Silicon Dioxide (SiO2)
mineral
Chert (Flint) with Limestone Matrix
Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)
sedimentary
Banded Sandstone (Water-worn Pebble)
Arenite with mineral banding
sedimentary
Gneiss (Granitic Gneiss)
Gneiss (composed primarily of Quartz, Feldspar, and Mica)
metamorphic
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
mineral
Chalcedony (Agate)
Silicon Dioxide (SiO2)
mineral
Weathered quartz-mica schist
Quartz–muscovite/biotite schist, locally iron-oxide stained
metamorphic
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz–mica schist or mica-rich quartzite
Quartz with muscovite/biotite mica; likely a quartz-mica schist, possibly pegmatitic
metamorphic
Veined Limestone
Sedimentary Calcite-Veined Rock (CaCO3)
sedimentary
Quartz Druzy
Crystalline Silicon Dioxide (SiO2)
mineral
Biotite on Quartz Matrix
Biotite - K(Mg,Fe)3(AlSi3O10)(OH,F)2 with Quartz (SiO2)
mineral
Milky quartz fragment
Quartz (silicon dioxide, SiO₂)
mineral
Sunstone
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
gemstone
Weathered sandstone fragment
Quartz-rich sandstone, likely feldspathic or lithic sandstone
sedimentary
Pyrite-bearing rock (likely pyrite-rich sulfide ore)
Pyrite, FeS₂, with possible dark host rock; exact matrix is not identifiable from the photo
mineral
Blue Chalcedony
Cryptocrystalline Quartz (SiO2)
mineral
Quartz-bearing weathered rock
Massive to drusy quartz (SiO₂), possibly in a feldspathic or carbonate host
mineral