This Is Not A Rock Or Mineral

Crushed Granite and Basalt

Phaneritic Igneous Rock / Aphanitic Igneous Rock

Quartz with Sericite and Cinnabar

Silicon Dioxide (SiO2) with muscovite/sericite and mercury sulfide (HgS)

Quartz-rich geode or mineralized cavity in host rock

Likely a quartz-bearing geode; the pale crystals may be quartz (SiO₂), but the photo is not detailed enough for a firm identification.

Geode

Quartz nodule / Chalcedony-lined cavity

Quartz-rich rock, likely granite or quartz-bearing metamorphic rock

Undetermined; possibly granitic rock composed mainly of quartz and feldspar, with mica or other dark minerals

Granite

Granite

River Rock / Stream Pebble

Fluvial Clast / Rounded Sedimentary Particle

Unidentified gray mineral/rock fragment

Indeterminate from the photograph; possibly a quartz- or feldspar-bearing rock fragment

Greenstone (likely chlorite- or epidote-rich metamorphic rock)

Greenstone; commonly metamorphosed basalt or dolerite, with chlorite, epidote, and actinolite

Weathered granite

Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, feldspars, and mica

Sandstone with Iron Banding

Arenite with Hematite or Limonite staining (SiO2 with Fe2O3)

Sandstone Pebble with Mineral Encrustation

Quartz Sandstone with Calcite/Halite Crust

Shale

Laminated Mudstone (Shale)

Smooth river pebble (exact rock type indeterminate)

Unidentified rounded lithic clast; composition cannot be determined from the photograph

Desert Rose

Gypsum (CaSO4·2H2O) or Barite (BaSO4)

Gravel or Crushed Stone

Fragmented Aggregate Stone

Granite

Felsic intrusive igneous rock

Polished dark-speckled igneous pebble, likely diorite or gabbro

Probable diorite (plagioclase feldspar and hornblende/biotite); exact identification is uncertain from the image

Granite Pebble

Intrusive Igneous Rock

Likely weathered granite or granitic gneiss

Granite: quartz + feldspar + mica; possibly gneiss if the faint texture reflects foliation

Quartz with Mafic/Chlorite Veins

Silicon Dioxide (SiO2) with Chlorite/Epidote cross-veining

Agate Geode

Silicon Dioxide (SiO2) - Chalcedony variety

Desert Rose (Baryte or Selenite variant)

Barium Sulfate (BaSO4) or Gypsum (CaSO4·2H2O) with Sand inclusions

Small tan mineral or rock fragment (unidentified)

Indeterminate from the image; no diagnostic features are visible

Yellow Agate (Banded Chalcedony)

Silicon Dioxide (SiO2)

Weathered iron-rich rock, possibly limonite-bearing basalt or laterite

Indeterminate; likely Fe-oxide/hydroxide–altered mafic rock, dominated by limonite/goethite with silicate minerals

Weathered Sedimentary Rock

Sedimentary Rock

Green serpentine-rich rock (possibly serpentinite)

Serpentinite, composed chiefly of serpentine-group minerals (e.g., lizardite, antigorite, or chrysotile)

Granite

Felsic intrusive igneous rock

Mixed Rock Collection (Pebbles and Stones)

Various geological specimens

Quartzite with Schist layers

Metamorphosed Quartz-rich Rock (Mixed Schist/Quartzite)

Weathered volcanic rock, likely andesite or basaltic-andesite

Fine-grained plagioclase–pyroxene volcanic rock; possible altered andesite (exact identification requires testing)

Sandstone with Manganese Dendrites

Clastic Sedimentary Rock (SiO2 based with MnO2 inclusions)

Vuggy Quartz on Matrix

Crystalline Silicon Dioxide (SiO2)

Quartz Geode

Silicon dioxide (SiO2)

Granite

Felsic intrusive igneous rock

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)

Granite

Phaneritic plutonic rock (primarily Quartz, Feldspar, and Mica)

Copper Ore (Malachite and Azurite stained rock)

Copper-bearing rock with secondary copper carbonates

Quartz Vein in Metamorphic Rock

Quartz-veined Schist or Gneiss

Sandstone

Arenite (SiO2 dominant)

River Pebble (Siltstone / Fine-grained Sandstone)

Sedimentary Pebble (Siliclastic)