Rock (Likely Sedimentary)

Small vesicular volcanic rock, likely scoria

Scoria; predominantly basaltic to andesitic volcanic rock

Serpentinized ultramafic rock (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals Mg₃Si₂O₅(OH)₄, with magnetite, olivine, and pyroxene remnants

Chert (Jasper-like)

SiO2 (Cryptocrystalline Quartz)

Concretion or Geode (unbroken)

Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.

Rounded gray stone, likely quartz-rich granitic rock

Probable granite or granitic gneiss; mainly quartz, feldspar, and mica

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Mixed mineral and rock collection

Predominantly quartz varieties, including amethyst, plus likely calcite, feldspar, mica, and miscellaneous polished stones

Rounded granite pebble

Granite, predominantly quartz, feldspar, and mica

White Quartz Pebble

Silicon Dioxide (SiO2)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Vesicular Basalt with Pyrite

Basalt (MgFe2+)(Si,Al)2O6 containing FeS2 inclusions

Milky Quartz with Matrix

Quartz (Silicon Dioxide, SiO2)

Quartz (Milky/Smoky variety on matrix)

Silicon Dioxide (SiO2)

Quartz (specifically Milky or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)

SiO₂ (silicon dioxide)

Basalt River Stone

Basalt

Schist

Crystalline Metamorphic Rock (Schistose)

Basalt

Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)

Man-made Carved Stone (Scream Mask/Skull motif)

Carved Soapstone or Serpentine-rich rock

Massive Quartz with Host Rock

Silicon Dioxide (SiO2)

Granite

Granite (Phaneritic Quartz-Feldspar Rock)

Polished Marble (likely Carrara-type with Iron oxides)

Metamorphosed Carbonate (CaCO3)

Red Jasper (Amygdaloidal Basalt with Agate)

Silicon dioxide (SiO2) in Basalt host

Small quartz-rich pebble

Quartz (SiO₂), possibly quartzite or weathered granite fragment

Weathered, iron-stained quartz-rich pebble (uncertain identification)

Microcrystalline quartz, SiO₂, with iron-oxide/hydroxide staining and dark matrix inclusions

Tumbled green aventurine (probable)

Quartzite dominated by quartz (SiO₂), with green mica/fuchsite or chlorite inclusions

Weathered quartz-rich pebble

Milky quartz, chiefly silicon dioxide (SiO₂), possibly with iron-oxide staining and minor feldspar

Polished brown mineral fragment, likely quartz-rich iron-stained material

Possibly quartz (SiO₂) with iron-oxide inclusions; exact identification is uncertain from the image

Rhyolitic Tuff (Breccia Type)

Rhyolitic Pyroclastic Rock (Mixed Silicates including Quartz, Feldspar, and Volcanic Glass)

Quartz Pebble

Silicon Dioxide (SiO2)

Fine-grained dark igneous rock, likely basalt

Basalt; predominantly plagioclase feldspar and pyroxene, commonly with minor olivine and iron-titanium oxides

Granite

Phaneritic Felsic Igneous Rock

Granite

Intrusive Igneous Rock (Granitic)

Granite

Phaneritic Igneous Rock (Granite)

Diorite

Phaneritic Intermediate Igneous Rock

Polished river pebble, likely granite or granitic gneiss

Quartz–feldspar–mica aggregate; possibly biotite granite (compositionally near granite)

Granodiorite

Granodiorite

Basalt (River Stone)

Basalt (Mafic volcanic rock)

Pink Anthracite Coal (dyed)

Anthracite Coal (Artificially Colored)

Quartz pebble in concrete

Quartz (SiO₂), embedded in Portland-cement concrete

Granite-like rock

Felsic intrusive igneous rock, likely granite or granodiorite