Gneiss
Gneiss (Metamorphic rock of variable composition, typically SiO2 rich)
Category
Browse metamorphic or igneous (context dependent) specimens identified by the Rock Identifier community.
Gneiss
Gneiss (Metamorphic rock of variable composition, typically SiO2 rich)
Banded Gneiss (River Cobble)
Gneiss (a high-grade metamorphic rock)
Milky Quartz
Silicon dioxide (SiO2)
Orange Calcite
Calcite (CaCO3)
Amazonite (Amazon Stone)
Tectosilicate Microcline (KAlSi3O8)
Amethyst
Amethyst (Silicon Dioxide with iron impurities, SiO2)
Pyrite
Iron Disulfide (FeS2)
Amethyst
SiO2 (Silicon Dioxide) - Purple variety of Crystalline Quartz
Citrine Quartz
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
Prehnite
Prehnite Ca2Al2Si3O10(OH)2
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Orange Calcite
Calcium Carbonate (CaCO3)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica/Amphibole)
Greenstone (Epidote/Chlorite-rich Metabasalt)
Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))
Quartz with Mica (Schist/Pegmatite fragment)
Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)
Schist
Schist (various mineral compositions)
Schist
Schist (various compositions)
Gneiss
Gneiss
Quartz on Greenstone
Silicon Dioxide (SiO2) on Altered Igneous Geologic Unit
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(OH)₄(BO₃)₃Si₆O₁₈)
Petrified Wood
Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz (specifically Citrine or Yellow Quartzite pebble)
Silicon Dioxide (SiO2)
Black Tourmaline (Schorl)
Schorl (Na(Fe^2+)3Al6(Si6O18)(BO3)3(OH)4)
Grey Agate (Banded Chalcedony)
Agate (Silicon Dioxide - SiO2)
Tumbled Moonstone and Amazonite Chips
Orthoclase (KAlSi3O8) and Microcline (KAlSi3O8) of the Feldspar Group
Milky Quartz
Quartz (Silica / Silicon Dioxide), SiO2
Milky Quartz
Quartz (Silica / Silicon Dioxide, SiO2)
Clear Quartz (Tumbled)
Quartz (Silicon Dioxide - SiO2)
Citrine Quartz
Citrine (Silicon Dioxide, SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Orange Calcite
Calcium Carbonate (CaCO3)
Yellow Quartz (Citrine Quartz Pebble)
Silicon Dioxide (SiO2)
Citrine Geode Fragment
Citrine (Silicon Dioxide with Iron Impurities), SiO2
Quartz (specifically Milky/Gray Quartz)
Silicon Dioxide (SiO2)
Sodalite
Sodalite (Na8Al6Si6O24Cl2)