Not A Natural Rock (Man Made Composite)

Dyed Blue Agate Slice

Silicon Dioxide (SiO2) with artificial dye

Granite

Intrusive Felsic Igneous Rock

Granite

Granite (composed mainly of Quartz, Alkali Feldspar, and Plagioclase)

Blue Sapphire (Raw)

Corundum (Al2O3)

Amethyst geode/druse

Quartz, SiO₂; purple variety amethyst

Red Jasper

Silicon Dioxide with iron impurities (Quartz variety, SiO2)

Shale or Mudstone (Based on appearance)

Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)

Silty Shale or Mudstone

Siltstone/Mudstone (Clastic Sedimentary Rock)

Sandstone with Iron Weathering

Quartz Arenite / Weathered Sandstone

Pink Granite

Phaneritic intrusive igneous rock (Granite)

Milky Quartz

Silicon Dioxide (SiO2)

Hag Stone

Perforated Sedimentary Rock (typically Sandstone or Siltstone)

Turquoise

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

River Cobble (likely Basalt or Greenstone)

Mafic Igneous Rock (with possible chloritic alteration)

Fulgurite

Fulgurite (Lechatelierite-rich fused silica)

Pegmatitic pink feldspar–quartz rock

Granitic pegmatite; chiefly microcline/orthoclase feldspar (KAlSi₃O₈), quartz (SiO₂), and minor mica

Rounded granite cobble

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Pink Dyed Agate (Pink Agate Slice)

Silicon Dioxide (SiO2) - Chalcedony / Cryptocrystalline Quartz

Weathered granite or granitic gneiss

Granite: quartz, feldspar, and mica; possibly weakly foliated gneiss

Blue Chalcedony (Tumbled)

Silicon Dioxide (SiO2)

Sandstone (Pebble/Conglomerate fragment)

Sandstone (clastic sedimentary rock)

Ferruginous Sandstone with Quartz Inclusions

Clastic Sedimentary Rock (Iron-rich Sandstone)

Limonite-coated Shale

Ferruginous Siliciclastic Shale

Druzy Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz Vein with Iron Staining

Silicon Dioxide (SiO2) with limonite/hematite staining

Agate

Silicon Dioxide (Chalcedony), SiO2

Druzy Quartz Geode (likely Smokey Quartz variety)

Silicon Dioxide (SiO2) - specifically a geode formation lined with druzy quartz crystals, with a likely brownish hue indicating smokey quartz.

Small rounded pebble

Indeterminate lithic grain; likely weathered sandstone, iron-stained quartz-rich rock, or a concretion

Rounded river pebble

Indeterminate; likely quartz-rich sandstone, chert, or weathered volcanic rock

Asphalt

Asphalt concrete

Polished orange agate/jasper cabochon

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide coloration; exact variety uncertain

Peridotite (Dunite/Peridot Xenolith)

Peridotite (predominantly Olivine (Mg, Fe)2SiO4)

Pumice

Pumice (Amorphous volcanic glass)

Turquoise

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

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Shale

Fissile Mudstone (primarily composed of clay minerals and quartz grains)

Greywacke (River Siltstone)

Lithic Wacke (Sandstone subfamily)

Rough Corundum (likely Sapphire/Zircon-bearing)

Aluminium Oxide (Al2O3)

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Conglomerate

Clastic sedimentary rock (Polymict conglomerate with quartz/calcite matrix)

Green Aventurine

Silicon Dioxide (Quartz variety) with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)