Biotite Schist
Biotite-bearing Schist (K(Mg,Fe)3AlSi3O10(F,OH)2)
Category
Browse sedimentary or metamorphic (base substrate) specimens identified by the Rock Identifier community.
Biotite Schist
Biotite-bearing Schist (K(Mg,Fe)3AlSi3O10(F,OH)2)
Kyanite
Kyanite (Al2SiO5)
Pyrite
Iron Pyrite (FeS2)
Quartz Veined Rock (Likely Graywacke or Quartzite)
Silicon Dioxide (SiO2) veins in Metasedimentary matrix
Mica Schist
Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)
Epidote
Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)
Polished gemstone tower assortment
Primarily quartz varieties and simulants; apparent amethyst (SiO₂), rose quartz (SiO₂), clear quartz (SiO₂), fluorite (CaF₂), sodalite, malachite, and possibly dyed or composite stones
Mica Schist
Mica Schist (KAl2(AlSi3O10)(OH)2)
Limonite after Pyrite (Prophecy Stone or Ironstone Concretion)
Goethite/Limonite pseudomorph after Pyrite/Marcasite (FeO(OH)·nH2O)
Graphite
Graphite (Native Carbon, C)
Mica / Muscovite or Biotite
Phyllosilicate mineral group (e.g., KAl2(AlSi3O10)(OH)2)
Biotite Schist
Biotite-rich Schist
River Stone (likely Quartzite or Limestone)
Silicon dioxide (SiO2) or Calcium carbonate (CaCO3)
Weathered gneiss
Foliated gneiss, chiefly quartz–feldspar–mica
Mica Schist
Mica Schist (Muscovite subclass)
Mica Schist
Mica Schist (primarily Muscovite and Biotite composition)
Mica Schist fragment
Mica Schist (KAl2(AlSi3O10)(OH)2 / K(Mg,Fe)3(AlSi3O10)(OH)2)
Mica Schist with Pyrite
Mica Schist (FeS2 containing)
Golden Mica Schist
Mica Schist (primarily Muscovite/Biotite with Quartz)
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Fuchsite Schist
Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2) in Schist
Mica Schist
Schist (Muscovite/Biotite Schist)
Schist
Mica Schist
Mica-rich metamorphic rock fragments
Biotite schist / mica schist (predominantly biotite, muscovite, and quartz)
Fossilized oyster shell
Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite
Biotite Schist
Biotite Schist
Zebra Jasper
Silicon Dioxide (SiO2) with various inclusions
Mica-rich metamorphic rock, likely schist
Muscovite–biotite schist, possibly with quartz and feldspar
Biotite Schist
Biotite-rich Schist
Mica Schist
Mica Schist (KAl2(AlSi3O10)(OH)2 - Muscovite component)
Mica Schist
Mica Schist (predominantly Muscovite or Biotite sheet silicates)
Metallic sulfide-rich rock, possibly pyrite-bearing schist or marcasite specimen
Likely pyrite (FeS₂) in a foliated host rock; exact identification requires testing
Weathered quartz-rich rock, possibly quartzite
Quartzite (mostly SiO₂), though the photograph is insufficient for confident identification
Mica Schist
Mica Schist (primarily Muscovite and Biotite KAl2(AlSi3O10)(OH)2)
Amethyst and mixed gemstone bracelet
Amethyst: purple quartz, silicon dioxide (SiO₂); likely accompanied by other quartz or decorative mineral beads
Bornite
Bornite (Cu5FeS4)
Desert rose
Gypsum (selenite) rosette, CaSO₄·2H₂O
Quartz with Mica inclusions (likely Schist or Gneiss host)
Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)
Weathered sandstone or iron-stained quartzite
Quartz-rich sandstone; possibly weakly metamorphosed quartzite (SiO₂ with iron-oxide coatings)
Anthracite Coal
Anthracite (Carbon-based sedimentary rock typically classified as metamorphic)
Likely biotite-rich mica schist
Mica schist, chiefly biotite (K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂); exact identification from image is uncertain
Blue Kyanite
Kyanite (Al2SiO5)