Biogenic Material

Ruby in Zoisite (Anyolite) or possibly a dyed stone/agate

Anyolite (Ruby in green zoisite) or artificially altered chalcedony

Quartz (Chert/Flint variety)

Silicon Dioxide (SiO2)

Chert / Flint

Silicon dioxide (Microcrystalline Quartz, $SiO_2$)

Chondrite Meteorite

Stony Meteorite (Ordinary Chondrite)

Rhinestone (or glass crystal)

Silicon dioxide (if glass) / Various

Weathered quartz-rich rock, possibly quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), identification uncertain from the photograph

Asphalt Pavement (with aggregate)

Asphalt concrete

Polished turquoise-colored stone, likely chrysoprase or dyed agate

Uncertain; possible chalcedony (microcrystalline SiO₂) or turquoise (hydrous copper aluminum phosphate)

Tumbled ruby in matrix

Corundum (Al₂O₃), commonly with mica, calcite, or other matrix minerals

Chert (likely flint)

Microcrystalline quartz, SiO₂

Granite or Pegmatite in host rock

Granitoid / Felsic Intrusive Rock

Orbicular gneiss (likely augen gneiss)

Quartz–feldspar–biotite gneiss; locally termed augen gneiss

Mica-rich metamorphic rock, likely schist

Quartz–mica schist; commonly quartz with muscovite and/or biotite mica

Dark green metamorphic rock, likely serpentinite

Serpentinite, chiefly serpentine-group minerals (antigorite/lizardite/chrysotile), commonly with magnetite and chromite

Mica schist (likely biotite–muscovite schist)

Mica schist; chiefly quartz (SiO₂) plus muscovite and biotite mica, with possible garnet or graphite

Likely raw blue kyanite specimens

Kyanite, Al₂SiO₅

Siltstone

Siltstone (primarily SiO2 with various silicates)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Possible weathered basalt or iron-rich volcanic stone

Fine-grained mafic rock, possibly basalt; exact identification requires testing

Quartz-rich metamorphic rock, likely quartzite

Quartzite, composed predominantly of quartz (SiO₂), with dark biotite, amphibole, or iron-oxide inclusions

Likely weathered igneous rock fragments

Indeterminate; possibly basaltic or granitic rock with quartz, feldspar, and dark mafic minerals

Iron-stained milky quartz vein

Quartz (SiO₂), with iron-oxide/hydroxide staining and minor dark inclusions

Polished/tumbled rhodonite-rich stone

Rhodonite (MnSiO₃), likely mixed with quartz and manganese oxides

White quartzite pebble

Quartzite; predominantly microcrystalline quartz (SiO₂)

Quartzite River Pebble

Quartzite (primarily SiO2)

Greenstone (Epidosite)

Epidosite (Metamorphosed Basalt/Diabase)

Asphalt (Bituminous Rock)

Natural bitumen or Bituminous limestone/sandstone

Polished banded calcite (often sold as “onyx marble” or Mexican onyx)

Banded calcite, CaCO₃ (sometimes aragonite); decorative “onyx marble” is not true quartz onyx

Natural turquoise-bearing rock

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O, likely in a limonite or host-rock matrix

Yellow jasper / iron-rich chert

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

Blue-green cabochon, likely chalcedony or treated glass imitation

Cryptocrystalline quartz (chalcedony/possibly chrysoprase); identification uncertain from image

Petrified Wood

Silicified Wood (SiO2)

Sandstone

Sandstone (Quartz-rich Arenite / SiO2)

Slag Glass

Silicon dioxide with impurities

Sandstone or similar clastic rock

Arenite

Limestone or Sandstone Cobble

Sedimentary rock (Calcium carbonate or Quartz based)

Quartz Vein in River Siltstone

Crystalline Quartz (SiO2) in Siliclastic Matrix

Pumice or Scoria

Vesicular volcanic rock

Milky Quartz Chip

Silicon Dioxide (SiO2)

Concrete fragment with Aggregate

Anthropogenic Concrete with Calcarious and Siliceous Aggregate

Sea Glass

Man-made vitreous material

Slag (Industrial Byproduct)

Anthropogenic Vitreous Silicate material