Mixed (Predominantly Sedimentary And Igneous)

General river rock or weathered cobble

Mixed rock composition

Beach Pebbles and Jasper

Quartz / Microcrystalline Silicon Dioxide (SiO2)

Pink Granite

Granite (Felsic Plutonic Rock)

Carnelian

Carnelian (SiO2)

Concrete fragment with Aggregate

Anthropogenic Concrete with Calcarious and Siliceous Aggregate

Concrete Fragment

Artificial Conglomerate (Cement and Aggregate)

Mixed rock and mineral specimen collection

Mostly undetermined from the photograph; apparent quartz-rich rocks, sandstone, granite/gneiss, and possibly iron-oxide-bearing specimens

Mixed rock and mineral specimen collection

Multiple species, likely quartz (SiO₂), calcite (CaCO₃), feldspar, chert, and assorted volcanic/sedimentary rocks

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)

Blue Chalcedony

Silicon Dioxide (SiO2)

Mixed River Stones and Minerals

Mixed Silica-rich Stones (Quartz, Agate, Jasper, Sandstone, Dalmation Stone)

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

Silver-colored mica schist

Muscovite–quartz schist, possibly with biotite

Soil with Mineral Detritus and Quartz Fragments

Regolith / Silicate Mineral Aggregate

Feldspar-Quartz Rock (likely Pegmatite or Granite)

Feldspar-Quartz composite rock (KAlSi3O8 - SiO2)

Granite Pebble

Granite (composed of Quartz, Feldspar, and Mica)

Pink Granite

Phaneritic Felsic Intrusive Igneous Rock

Mixed River Pebbles (including Unakite and Jasper)

Polymineralic geological specimens

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Aventurine (Green Quartz)

Silicon Dioxide (SiO2) with inclusions of Fuchsite (Mica)

Tumbled Agate

Silicon Dioxide (Chalcedony variety), SiO2

Sodalite

Na4Al3(SiO4)3Cl (Sodium Aluminum Silicate Chloride)

Quartz pebble

Silicon dioxide (SiO2)

Asphalt (Bituminous Rock)

Natural bitumen or Bituminous limestone/sandstone

Assorted Decorative Tumbled Stones (Quartz, Sodalite, Aventurine, Calcite)

Mixed Silicates and Carbonates (SiO2, Na8(Al6Si6O24)Cl2, CaCO3)

Assorted Tumbled Gemstones

Mixed oxides and silicates (including Quartz, Chalcedony, and Feldspar variants)

Smoky Quartz and Orthoclase Feldspar

Granitic Pegmatite (SiO2 + KAlSi3O8)

Asphalt

Asphalt concrete

Fulgarite

Fulgurite (Lechatelierite / Vitrified Sand)

Mixed polished river stones

Likely quartz, quartzite, chert/jasper, and possibly limestone or marble

Rounded river gravel (mixed alluvial pebbles)

Polymictic alluvial gravel; commonly composed of quartzite, granite, basalt, sandstone, and quartz

Glacially transported granite and gneiss boulders

Granite (quartz–feldspar–mica); banded specimens likely gneiss

Caribbean Calcite

Calcite (CaCO3) with Aragonite (CaCO3)

Dalmatian Stone (Dalmatian Jasper)

Peralkaline Quartz-Feldspar Porphyry with Arfvedsonite

Mixed polished river pebbles, predominantly quartzite and quartz

Quartzite (SiO₂), quartz (SiO₂), with possible feldspar-rich and iron-stained lithologies

Granite

Granite (Plutonic Igneous Rock)

Pink Granite

Phaneritic Felsic Igneous Rock

Mixed river-worn rock and mineral collection

Mostly quartz/quartzite, feldspar-bearing granitoid, chert, and mafic volcanic rocks; exact species vary by pebble

Hematite cameo or hematine imitation

Hematite (Fe₂O₃); possibly synthetic hematine or black glass

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Mixed gemstone jewelry collection

Various gemstone minerals, including likely amethyst (quartz), sapphire or iolite, garnet, pearl, turquoise, and colored beryl or tourmaline

Mixed river stones and gravel

Polymictic alluvial clasts; individual pieces may include quartzite, granite, basalt, sandstone, limestone, and slate