Man Made Material, Not A Natural Rock Or Mineral Specimen

Pink chalcedony (likely rough agate/chalcedony)

Microcrystalline quartz, SiO₂; chalcedony variety, possibly iron-bearing

Smoky Quartz

Smoky Quartz (Silicon Dioxide - SiO2)

Tumbled blue-green stone, likely chrysocolla-bearing jasper

Chrysocolla-rich chalcedony/jasper; commonly a mixture of chrysocolla (hydrated copper silicate, variable formula) and quartz (SiO₂)

Garnet

Almandine (Fe3Al2(SiO4)3)

Sandstone (Ferruginous)

Arenite (with high iron oxide content)

Vesicular Basalt River Rock

Vesicular Basalt

Mica-rich metamorphic rock, likely schist

Muscovite–biotite schist, possibly with quartz and feldspar

Likely obsidian (possibly tektite or slag glass)

Volcanic glass; primarily SiO₂, noncrystalline

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Iron Oxide cement)

Polished black obsidian pyramid/block

Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)

Blue-gray metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica assemblage; exact identification requires testing

Hag Stone

Perforated Sedimentary Rock (typically Limestone or Sandstone)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with Iron impurities)

Granitic Pebble (Glacial Erratic)

Granite

Diamond (or Cubic Zirconia)

Carbon (C) or Zirconium Dioxide (ZrO2)

Slate

Slate (Foliated Metamorphic Rock)

Diamond

Pure Carbon (C)

Slag

Anthropogenic Vitrification Product / Silicate Slag

Vesicular volcanic rock, likely weathered scoria

Scoria (vesicular basaltic-andesitic volcanic rock), composition approximately plagioclase, pyroxene, and volcanic glass

Sandstone

Arenite (SiO2 principal component)

Granite Pebble

Granite

Polished red jasper

Jasper, opaque microcrystalline quartz (SiO₂) colored mainly by iron oxides

Likely chlorite-bearing schist (possibly greenschist)

Chlorite–quartz–mica schist; commonly contains muscovite/biotite and feldspar

Schist

Mica schist, likely muscovite–biotite schist with quartz and feldspar

Likely milky quartz fragment

Quartz (silicon dioxide, SiO₂), possibly with iron-oxide or mica inclusions

Citrine

Silicon Dioxide (SiO2) with iron impurities

Basalt River Stone

Basalt (extrusive igneous rock)

Pink Granite

Granite (enriched in Potassium Feldspar / Orthoclase)

Diorite

Diorite (intermediate intrusive igneous rock)

Quartz-rich breccia or quartzite with iron-oxide veining

Microcrystalline to granular SiO₂ (quartz), with hematite/goethite and minor feldspar or mica

Diamond

C (Carbon)

Botryoidal chalcedony (likely white quartz/chalcedony)

Microcrystalline quartz, SiO₂; possibly partly altered carbonate or opaline silica

Green aventurine (likely)

Quartzite dominated by quartz (SiO₂), colored green by fuchsite mica or chlorite

Quartzite River Rock

Quartzite (primarily SiO2)

Quartz Druze (on Matrix)

Silicon Dioxide (SiO2)

Turquoise

Hydrated phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O

Faceted Clear Quartz or Diamond Simulant

Silicon Dioxide (SiO2) if Quartz or Cubic Zirconia (ZrO2) if Synthetic

Banded Agate (Onyx type)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Rounded brown-gray stone, possibly weathered conglomerate or sandstone

Indeterminate clastic sedimentary rock; likely poorly cemented sandstone/conglomerate

Quartz with Iron Stains

Silicon Dioxide (SiO2) with FeOx inclusions

Fossiliferous Limestone

Fossiliferous Limestone (CaCO3)

Pearl

Aragonite (CaCO3) with Conchiolin