Man Made Material, Not A Natural Rock Or Mineral Specimen

Sandstone

Arenite (composed primarily of SiO2)

Ceramic or Polished Stone Heart (Anthropogenic Material)

Glazed Ceramic (Silicon Dioxide based coating on Alumina Silicate body) or Polished Limestone/Marble (Calcium Carbonate, CaCO3)

Chert

Microcrystalline Quartz (SiO2)

Tumbled gray feldspar-rich stone, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, potentially fine-grained granite or quartzite

Tumbled purple agate (likely grape agate or amethystine chalcedony)

Microcrystalline quartz, SiO₂; purple coloration commonly from iron, manganese, or inclusions

Ferro-slag (Leland Blue/Slag Glass)

Anthropogenic Vitreous Silica (Industrial Slag)

Generic Rock Fragment

Rock Fragment

Desert Rose (Gypsum Rose)

Calcium Sulfate Dihydrate (CaSO4·2H2O)

Clear quartz sphere or polished quartz cabochon (tentative)

Quartz, silicon dioxide (SiO₂); appearance may also be consistent with ordinary glass, which cannot be ruled out from the image alone

Dyed Quartz Geode

Silicon Dioxide (SiO2) with artificial purple dye

Engineered Quartz (Quartzite look-alike)

Silicon Dioxide (SiO2) composite

Asphalt (Bituminous Concrete)

Bituminous mix / Anthropogenic conglomerate

Small polished brown stone

Indeterminate; possibly tumbled jasper, brown agate, or another iron-stained silicate

Basalt River Stone

Basalt

Polished dark stone, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine

Sandstone (Quartzose)

Arenite (composed primarily of SiO2)

Red Sandstone

Sandstone (Quartz Arenite / Arkose with Hematite cement)

Sandstone

Arenite (primarily SiO2)

Jasper Marble

Silicon Dioxide (SiO2) with Impurities

Sandstone

Arenite (SiO2 composition dominant)

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2

Corundum (Ruby variety)

Aluminium oxide (Al2O3)

Granite

Intrusive Felsic Igneous Rock (primarily Quartz and Feldspar)

Granite

Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)

Tumbled or rough turquoise-like specimen

Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O; identification is uncertain from the image

Tree Agate

Chalcedony (SiO2)

Sandstone

Arenite (SiO2 based clastic rock)

Clay Brick

Ceramic structural unit (Al2O3·2SiO2·2H2O as precursor)

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

Hydrated iron oxides/hydroxides, chiefly limonite-goethite mixture; exact identification requires testing

Sandstone

Arenite (SiO2, often with CaCO3 or Fe2O3 cement)

Sea Glass (specifically Frosted White)

Amorphous Silica (substance: Sodium-calcium silicate glass)

Quartz with Mafic/Chlorite Veins

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

Sandstone Concretion

Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)

Flint

Silicon dioxide (SiO2)

Geode / Fossilized Gastropod or Shell Cast

Silicon dioxide (Quartz) replacement / fossil mold

Blue Cat's Eye Quartz (Heated/Dyed)

Silicon Dioxide (SiO2) with fibrous inclusions

Sandstone

Arenite (primarily Quartz-rich)

Quartz (Smoky Quartz variant)

Silicon Dioxide (SiO2)

Sandstone (likely Greywacke or Siltstone variety)

Arenite / Siltstone (primarily SiO2)

Blue Goldstone

Aventurine Glass (SiO2 with Cobalt/Copper inclusions)

Sandstone pebble

Clastic sedimentary rock (primarily SiO2)

Likely pale limestone or calcite-rich rock

Calcite-bearing limestone; chiefly calcium carbonate (CaCO₃)