Anthropogenic Sedimentary (Man Made)

Dyed Quartz (often sold as 'Blue Quartz' or 'Blue Agate')

Silicon Dioxide (SiO2) with artificial pigment

Granite

Granite (a common rock type, not a single mineral with a formula. Composed primarily of quartz, feldspar, and mica/amphibole).

Granite

Granite (felsic intrusive igneous rock)

Diamond

Carbon (C)

Weathered pegmatite or feldspar-rich granite fragment

Granitic pegmatite, composed mainly of potassium feldspar and quartz, with minor mica; exact identification is uncertain from the photograph

Amber (Copal)

Organic gemstone, fossilized tree resin (often immature amber or copal)

Fossilized Stingray Mouth Plate

Myliobatidae gen. et sp. indet. (e.g., Myliobatis, Aetobatus)

Petoskey Stone

Hexagonaria percarinata

Sea Glass (Frosted Glass)

Amorphous Silica (SiO2) with various metal oxide impurities

Metal Alloy (Jewelry)

Not a naturally occurring rock or mineral; likely a metal alloy for jewelry. Possible compositions include sterling silver (92.5% silver, 7.5% copper), or other silver/gold alloys.

United States Quarter Dollar

Cupronickel Clad Alloy (75% Copper, 25% Nickel over a 100% Copper core)

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Goldfish Cracker (Culinary Mimic)

Cibus aurum (Commonly composed of Enriched Wheat Flour and Cheddar Cheese)

Obsidian

Obsidian (volcanic glass, amorphous silica rich rock)

Quartz

Silicon Dioxide (SiO₂)

BROWN GRANITE (likely 'Tan Brown' or similar)

Granite (specifically a variety rich in orthoclase feldspar, often with biotite and possibly hornblende)

Mixed Gemstone Beaded Jewelry

Various minerals (e.g., Quartz varieties like Rose Quartz, Amethyst; Peridot; Garnet; etc.)

Granite, possibly granodiorite

Coarse-grained felsic plutonic rock; chiefly quartz (SiO₂), potassium feldspar and plagioclase feldspar, with biotite and/or hornblende

Goldstone

Not a natural mineral or rock. It is an ornamental glass.

South Korean 100 Won Coin (Cupronickel)

Cupronickel Alloy (75% Cu, 25% Ni)

Efflorescence (on Clay Brick)

Crystalline salt deposits (typically Sodium Sulfate Na2SO4, Calcium Carbonate CaCO3, or Potassium Sulfate K2SO4)

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2

Tumbled sodalite with white calcite veining

Sodalite, Na8(Al6Si6O24)Cl2, commonly intergrown with calcite, CaCO3

Granite Cobble/Pebble

Granite

Granite (weathered pebble)

Granite (plutonic igneous rock)

Jade (likely Nephrite Jade based on appearance)

Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2)

Titanium Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

Titanium Coated Aura Quartz (Apple Aura Quartz)

Silicon Dioxide (SiO2) with Metallic Vapor Deposition Coating

Serpentinite

Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)

Obsidian

Obsidian (volcanic glass)

Cullet Glass (Industrial Slag Glass)

Amorphous Silica (SiO2) with metallic oxide impurities

Chert (Flint)

Silicon Dioxide (SiO2)

Glazed Ceramic Tile

Fused Silicate-Clay composite

Basalt

Basalt

Granite

Granite (a common rock name, not a single mineral species, composed primarily of quartz, feldspar, and mica/amphibole)

Iron Slag

Vitreous glassy waste (Fe-Si-Al-Ca compounds)

Sandstone

Arenite (SiO2 dominant)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

White Jade (Nephrite)

Nephrite, Ca2(Mg,Fe)5Si8O22(OH)2

Siltstone / Slate

Siltstone / Low-grade Slate