Mineral (Man Enhanced)

Carnelian (Agate)

Carnelian (Silica, SiO2)

Blue Dyed Agate Slice

Silicon Dioxide (SiO2) with artificial pigment

Diamond (or Diamond Simulant)

Carbon (C)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), opaque-to-translucent milky variety

Purple Turquoise (Composite Mojave Turquoise)

CuAl6(PO4)4(OH)8·4H2O (Hydrated copper aluminum phosphate composite)

White Howlite

Howlite (Hydrated calcium borosilicate, Ca2B5SiO9(OH)5)

Faceted Glass (Costume Jewelry)

Amorphous Silicon Dioxide with colorants (Glass)

Green Banded Agate

Agate (Variety of Chalcedony/Quartz), SiO2

Concrete

Anthropogenic Conglomerate

Blue Lace Agate

Cryptocrystalline Quartz (SiO2) with trace minerals

Silver Flakes in Glass

Silver (Ag)

Carnelian (orange chalcedony)

Chalcedony, microcrystalline quartz (SiO₂), iron-colored variety

Goldstone

Aventurine Glass (Man-made)

Blue opalite glass cabochon (likely imitation opal)

Man-made opalescent glass; not a natural mineral

Corundum (Pink Sapphire / Ruby)

Al2O3 (Aluminum Oxide)

Sea Glass

Man-made vitreous material

Polished dendritic agate or jasper

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions

Agate

Banded Chalcedony (SiO2)

Diamond (in jewelry setting)

Diamond (C - Carbon)

Blue-green fluorite (likely tumbled/polished)

Fluorite, calcium fluoride (CaF₂)

Orange chalcedony / carnelian with drusy quartz

Microcrystalline quartz, SiO₂ (chalcedony; iron-colored variety often called carnelian), with possible calcite or quartz matrix

Carnelian

SiO2 (Silicon Dioxide, variety of Chalcedony)

Red glassy gemstone, possibly garnet

Unidentified red transparent material; garnet group (X₃Y₂(SiO₄)₃) is a possibility

Tumbled honey-yellow quartz/chalcedony, possibly dyed

Microcrystalline quartz (SiO₂), likely chalcedony or quartz with iron-oxide coloration

Yellow calcite (likely polished/tumbled)

Calcite, calcium carbonate (CaCO₃)

Tumbled yellow chalcedony

Microcrystalline quartz (SiO₂), likely yellow jasper or chalcedony

Banded Agate (Pink/White)

Silicon Dioxide (SiO2) - Variety of Chalcedony

Polished leopard jasper

Rhyolitic jasper/chalcedony aggregate, commonly sold as leopard jasper

Tumbled chalcedony (likely blue-gray agate)

Cryptocrystalline quartz, SiO₂; chalcedony/agate variety

Sea Glass

Silicon dioxide (mostly)

Polished fossil coral (likely fossilized honeycomb or tabulate coral)

Fossilized tabulate coral; commonly Favosites or related genera, preserved mainly as calcite (CaCO₃)

Crackled Quartz (Dyed)

Silicon Dioxide (SiO2)

Quartz pebble (Quartztite fragment)

Silicon Dioxide (SiO2)

Tumbled carnelian/chalcedony

Orange chalcedony, microcrystalline quartz (SiO₂), likely iron-oxide-bearing

Polished serpentine (likely greenstone)

Serpentine-group minerals, chiefly antigorite/lizardite: Mg₃Si₂O₅(OH)₄

Black-and-white agate geode pendant

Agate (microcrystalline quartz, SiO₂), likely a hollow geode slice with chalcedony and drusy quartz

Diamond

Carbon (C)

Carnelian (Orange Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Agate (Polished Nodule)

Agate (Silicon Dioxide, SiO2)

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Concrete Fragment

Hardened Portland cement and mineral aggregate

Citrine Quartz carving

Silicon Dioxide (SiO2)