Banded gneiss pebble
Gneiss, composed chiefly of quartz, feldspar, and mica/amphibole
metamorphic
Category
Mineral (Native Element Alloy)
Browse mineral (native element alloy) specimens identified by the Rock Identifier community.
Learn about Mineral (Native Element Alloy) in the encyclopedia
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Shark Tooth Fossil
Otodus obliquus (or similar prehistoric lamniform shark tooth)
fossil
Fossil Shark Tooth
Chondrichthyes (class)
fossil
Fossilized Shell Fragment
Bivalvia or Gastropoda (Class) fragment
fossil
Silicon Carbide (Carborundum)
Moissanite (SiC)
mineral
Gneiss (River Cobble)
Gneiss
metamorphic
Fluorite on Matrix
Calcium Fluoride (CaF2)
mineral
Bicolor or Tricolor Tourmaline
Elbaite (Na(Li,Al)3Al6(BO3)3Si6O18(OH)4)
mineral
Coquina / Shelly Limestone
Coquina (calcium carbonate, CaCO3)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Calcareous or Siliceous Matrix
mineral
Agate / Chalcedony Geode
Silicon Dioxide (SiO2)
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Note regarding baguette production (not a rock)
Digital text image - Somali language
not a rock
Pyrite (or Arsenopyrite / Ore mineral aggregate)
FeS2 (Iron Sulfide)
mineral
Pink Feldspar
Potassium Feldspar (KAlSi3O8)
mineral
Potassium Feldspar (Orthoclase / Microcline)
KAlSi3O8 (Potassium Aluminum Silicate)
mineral
Quartz (Druzy or Chalcedony variant)
Silicon Dioxide (SiO2)
mineral
Granite Gneiss
Gneiss (Derived from Granite protolith)
metamorphic
Amygdaloidal Basalt
Extrusive Igneous Rock with Amygdules
igneous
Schist (Greenschist / Mica Schist)
Metamorphic rock rich in platy minerals (e.g., Chlorite/Mica schist)
metamorphic
Limonite on Sandstone
Iron Oxyhydroxide (FeO(OH)·nH2O) on Quartz Sandstone
sedimentary
Quartz (Druzy / Crystalline)
Silicon Dioxide (SiO2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Obsidian
Volcanic Glass (SiO2)
igneous
Snowflake Obsidian
Obsidian with Cristobalite inclusions (SiO2)
igneous
Blue Sapphire
Corundum (Al2O3 with Cr, Fe, and Ti trace elements)
gemstone
Vesicular volcanic rock, likely scoria
Scoria; composition commonly basaltic to andesitic, rich in plagioclase and pyroxene
igneous
Fossilized Stingray Mouth Plate
Myliobatidae gen. et sp. indet. (e.g., Myliobatis, Aetobatus)
fossil
Unakite
Altered Granite (Epidotized Granite)
metamorphic
Granite Glacial Erratic
Intrusive Phaneritic Felsic Rock (Granite)
igneous
Mica Schist
Mica Schist (primarily Muscovite or Biotite sheet silicates)
metamorphic
Greenschist (Chlorite Schist)
Greenschist (Metamorphic rock dominated by chlorite, actinolite, and epidote)
metamorphic
Epidote
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
metamorphic
Epidote
{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
mineral
Epidote
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
metamorphic
Epidote
Epidote ({Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH))
mineral
Not a rock, mineral, or geological specimen
N/A
Likely weathered quartz-bearing rock fragment
Indeterminate; appears to contain quartz (SiO₂) with iron-oxide staining, possibly from quartzite, granite, or pegmatite
mineral
Quartz-rich pegmatite with mica and dark inclusions
Pegmatite; chiefly quartz (SiO₂), with feldspar and biotite/tourmaline inclusions
igneous
Fossilized Bone
Petrified Bone / Biogenic Sedimentary
fossil
Chakra Crystal Bracelet
Mixed Mineral Assortment
gemstone