Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
Category
Browse mineral based composite specimens identified by the Rock Identifier community.
Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
Quartzite
Hydrothermal Quartz or Quartzite (SiO2)
Garden Quartz
Included Quartz (SiO2 with accessory minerals such as Chlorite, Hematite, or Feldspar)
Granite
Granite (Phaneritic Quartz-Feldspar intrusive rock)
Basalt with Caliche Crust
Aphanitic Mafic Igneous Rock with Calcium Carbonate (CaCO3) coating
Moss Agate and Druzy Quartz Carving
Cryptocrystalline Silica (SiO2) with impurities
Dendritic Agate
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
Citrine
Silicon dioxide (SiO2)
Strawberry Quartz
Silicon Dioxide (SiO2) with Hematite/Goethite inclusions
Siltstone with iron staining
Siltstone (primarily SiO2 with FeO(OH) coatings)
Basalt
Basalt (Mafic Extrusive Igneous Rock)
Sandstone (Quartzose Sandstone)
Arenite (SiO2)
Biotite (Mica)
Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)
Olivine-bearing Basalt / Scoria
Mafic Igneous Rock (primarily (Mg, Fe)2SiO4)
Milky Quartz with Mica (Gneiss/Schist influence)
Silicon Dioxide (SiO2) with Phyllosilicates
Lepidolite Polished Point
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
Mica Schist
Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)
African Turquoise
African Turquoise (a trade name for Jasper, a variety of Chalcedony: SiO2)
Fuchsite (Green Muscovite)
K(Al,Cr)2(AlSi3O10)(OH)2
Fuchsite
Chromium-bearing Muscovite - K(Al,Cr)2(AlSi3O10)(OH)2
Granite
Granite (Phaneritic igneous rock)
Jade (likely Jadeite)
Jadeite (a pyroxene mineral) or Nephrite (a variety of amphibole mineral)
Vesicular Basalt
Amygdaloidal Basalt (Mafic extrusive volcanic rock)
Granite
Phaneritic plutonic rock (primarily Quartz, Feldspar, and Mica)
Peacock Ore (Bornite or Chalcopyrite treated with acid)
Bornite (Cu5FeS4) or Acid-washed Chalcopyrite (CuFeS2)
Muscovite (White Mica)
Muscovite - Potassium aluminum silicate: KAl2(AlSi3O10)(F,OH)2
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
Dendritic Opal (Merlinite)
Hydrated Silica with Manganese/Iron oxide inclusions (SiO2·nH2O)
Fuchsite
Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)
Blue Celestite (Celestine)
Strontium sulfate (SrSO4)
Pink Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
Amygdaloidal Basalt
Amygdaloidal Basalt
Purple Lepidolite with Quartz
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
Basalt with Quartz/Zeolite Inclusions
Porphyritic Basalt (SiO2 with Aluminosilicates)
Feldspathic Granite (likely Syenite or Granite Pegmatite)
Phaneritic Acidic Igneous Rock (KAlSi3O8 dominant with SiO2)
Sandstone
Clastic Sedimentary Rock (composed primarily of Quartz, SiO2)
Granite
Phaneritic Felsic Igneous Rock
Citrine
Silicon Dioxide (SiO₂)
Conglomerate
Conglomerate (Clastic Sedimentary Rock)
Snowflake Obsidian
Spherulitic Obsidian (Amorphous volcanic glass with Phenocrysts of Cristobalite)
Slag (Industrial Glass Slag)
Amorphous Silicate Glass (often containing Al, Ca, Mg, and Ti oxides)
Amygdaloidal Basalt
Basalt with secondary mineral infilling