Sandstone (Iron-stained)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
sedimentary
Category
Igneous And Metamorphic Derivative (Weathered)
Browse igneous and metamorphic derivative (weathered) specimens identified by the Rock Identifier community.
Limonite (Yellow Ochre)
FeO(OH)·nH2O (Hydrous iron(III) oxide-hydroxide mixture)
Mineral (Iron Ore)
Turquoise
Hydrated copper and aluminum phosphate (CuAl6(PO4)4(OH)8·4H2O)
mineral
Gneiss (specifically a Banded Gneiss pebble)
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Pyrite on Quartz
Iron Sulfide (FeS2) on Silicon Dioxide (SiO2)
mineral
Quartz (Milky/Cloudy Variety)
Silicon Dioxide (SiO2)
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Blue Quartz with Dumortierite/Magnesio-riebeckite inclusions
Quartz (SiO2) containing Dumortierite (Al7(BO3)(SiO4)3O3)
igneous/metamorphic
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Citrine Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Field Stone)
Chert (SiO2)
sedimentary
Citrine
SiO2 (Silicon Dioxide)
Mineral
Granite (tumbled pebble)
Granite (Plutonic Igneous Rock)
Igneous Rock
Smoky Quartz
SiO2 (Silicon Dioxide)
Mineral
Citrine
Quartz (SiO₂) variety
Mineral
Black Star Diopside
Diopside (CaMgSi2O6) with asterism
Mineral
Apatite
Apatite group mineral (e.g., Fluorapatite - Ca5(PO4)3F, Chlorapatite - Ca5(PO4)3Cl, Hydroxylapatite - Ca5(PO4)3(OH))
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica/Amphibole)
metamorphic
River Pebbles (Stream-rounded rocks)
Fluvial Detritus (varied mineralogy)
Mixed (predominantly sedimentary and igneous)
Pallasite Meteorite
Pallasite (Stony-iron meteorite; Fe-Ni alloy with (Mg,Fe)2SiO4 olivine)
Mineral/Extraterrestrial Rock
Banded Gneiss (River Cobble)
Gneiss (a high-grade metamorphic rock)
metamorphic
Marble
Marbles are primarily composed of calcite (calcium carbonate, CaCO3) or dolomite (calcium magnesium carbonate, CaMg(CO3)2).
Metamorphic Rock
Milky Quartz
Silicon dioxide (SiO2)
mineral
Amazonite (Amazon Stone)
Tectosilicate Microcline (KAlSi3O8)
mineral
Amethyst
SiO2 (Silicon Dioxide) - Purple variety of Crystalline Quartz
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
mineral
Prehnite
Prehnite Ca2Al2Si3O10(OH)2
mineral
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Greenstone (Epidote/Chlorite-rich Metabasalt)
Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))
metamorphic
Orange Calcite
Calcite (CaCO3)
Mineral
Milky Quartz (Water-Worn Pebble)
Quartz (Silicon Dioxide, SiO2)
mineral
River Rock (Glacial Cobbles)
Fluvial Alluvium (Mixed lithology including Quartzite, Basalt, and Granite)
Mixed (predominantly sedimentary and igneous)
Orthoclase Feldspar (or K-Feldspar)
Orthoclase (KAlSi3O8)
Mineral