This Is Not A Rock Or Mineral

Serpentine (rough serpentine-rich rock)

Serpentine-group minerals, chiefly antigorite and/or lizardite; composition broadly Mg₃Si₂O₅(OH)₄

Quartz-veined metamorphic rock, likely greenschist or altered metavolcanic

Chlorite–actinolite–epidote-bearing metavolcanic rock with quartz veins; exact identification requires testing

Gneiss

Gneiss (Metamorphic Rock)

Likely garnet-bearing rock (possibly almandine garnet in dark matrix)

Garnet, probably almandine (Fe₃Al₂(SiO₄)₃); host rock is not identifiable from this image

Iron-stained Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite inclusions

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Sandstone (Weathered Fragment)

Clastic Sedimentary Rock

Desert Varnish on Sandstone

Ferromanganese coating on Quartz Arenite

Porphyry (Porphyritic Basalt / Andesite)

Porphyritic Igneous Rock

Small pale blue-gray rock fragment

Unidentified fine-grained silicate rock; image insufficient for a reliable species-level identification

Granite

Felsic intrusive igneous rock

Painted pebble, likely a smooth river stone

Unidentified fine-grained natural rock; exact lithology cannot be determined from the image

Quartz Druzy

Silicon Dioxide (SiO2)

Blue-gray quartz-rich rock, possibly blue aventurine or sodalite-bearing stone

Probable quartz–feldspar aggregate; exact identification requires testing

Garnet-bearing rock (likely almandine garnet in a metamorphic matrix)

Almandine garnet, Fe₃Al₂(SiO₄)₃; host rock is uncertain from the image

Pink granite pebble

Granite, composed chiefly of quartz, potassium feldspar, and mica

Sandstone (Banded)

Clastic Sedimentary Rock: Arenite

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Quartz-rich granite (likely leucocratic granite)

Granite, composed mainly of quartz and feldspar with minor dark minerals

Basalt with Iron Oxidation (Lattice/Veined)

Mafic Volcanic Rock (principally Plagioclase and Pyroxene)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Greenstone (likely chlorite- or actinolite-rich metabasalt)

Metamorphosed mafic volcanic rock; commonly greenschist-facies basalt, composed chiefly of chlorite, actinolite, epidote, and albite

Gneiss

Quartz–feldspar–mica gneiss

Rhyolite with Lithophysae and Iron Oxide

Extrusive igneous rock / Felsic volcanic rock

Granite Core Sample

Granite

Granite

Granite (felsic intrusive igneous rock)

Quartz-rich gravel fragment

Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions

Porphyritic Basalt

Porphyritic Basalt with Plagioclase Phenocrysts

Granite

Intrusive Igneous Rock

Hag Stone (Adder Stone / Geode-bearing Pebble)

Sedimentary Rock with Cavity (often Quartzite, Limestone, or Sandstone)

Geode with Quartz and possibly Jasper/Hematite

Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides

Banded Igneous Dike Rock

Intrusive igneous rock with felsic/mafic banding

Basalt with Quartz Vein

Mafic Igneous Rock (SiO2 filling)

Layered metamorphic rock, possibly banded gneiss

Gneiss (tentative; exact identification requires closer examination)

Granite

Felsic intrusive igneous rock

Banded metamorphic rock, likely gneiss

Foliated quartz–feldspar rock (gneiss; exact identification requires closer examination)

Moonstone

Orthoclase Feldspar (KAlSi3O8)

Quartz Geode

Silicon Dioxide (SiO2) within a geode

Sandstone (with secondary weathering/concretion)

Arenite (composed primarily of Quartz, SiO2)

Uncertain small tan mineral/rock fragment

Indeterminate from image; possibly feldspar-rich rock or calcite

Chrysocolla on Matrix

Hydrated copper silicates ((Cu,Al)2H2Si2O5(OH)4·nH2O)