Man Made Composite

Polished red jasper beads

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Pink calcite (likely)

Calcite — calcium carbonate, CaCO₃

Tumbled greenstone / serpentinite (probable)

Serpentinite, chiefly Mg-rich serpentine minerals (antigorite, lizardite, chrysotile), possibly mixed with chlorite, magnetite, or carbonate

Diamond

Carbon (C)

Diamond

Carbon (C)

Polished black stone, likely basalt or black jasper

Indeterminate; possible fine-grained basalt (plagioclase–pyroxene) or black jasper/microcrystalline quartz

Tumbled chalcedony (likely blue-gray agate)

Cryptocrystalline quartz, SiO₂; chalcedony/agate variety

Chert (Flint)

Microcrystalline Quartz (SiO2)

Coal (Anthracite / Bituminous)

Organic Sedimentary Rock (Carbon-based)

Chert / Green Jasper

Silicon Dioxide (SiO2)

Clear calcite cleavage fragment

Calcite (calcium carbonate, CaCO₃)

Granite Pebble

Granite (Phaneritic Quartz-Feldspar Rock)

Granite (River Cobble)

Phaneritic Plutonic Felsic Rock (Granite)

Granite / Quartzite Specimen

Granite / Quartz (SiO2 with Feldspar and Mica)

Vesicular basalt (likely)

Basalt; chiefly plagioclase, clinopyroxene, and olivine, with possible iron-oxide alteration

Green Banded Chert (Agate/Jasper)

Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite

Beaded blue-and-green gemstone jewelry

Likely dyed or treated chalcedony/agate and green aventurine or glass-like stone; exact identification requires testing

Peridotite (Dunite)

Olivine-rich Peridotite ((Mg,Fe)2SiO4)

Carbonate Beach Sand

Biogenic Carbonate Sediment (CaCO3)

Raw calcite specimen

Calcite, calcium carbonate (CaCO₃)

Likely basalt

Mafic volcanic rock, chiefly plagioclase and pyroxene, commonly with minor olivine and magnetite

Granite

Phaneritic Felsic Igneous Rock

Granite Pebble

Granite (Phaneritic intrusive rock)

Granite

Granite (Felsic Plutonic Rock)

Gemstone bead necklace (likely citrine or yellow quartz)

Quartz, SiO₂; precise identification is uncertain because the beads are blurred and metal settings obscure them

Amethyst bead bracelet

Amethyst, purple quartz (SiO₂), with likely dyed or heat-treated agate/carnelian beads

Native Silver

Silver (Ag)

Diamond

Carbon (C)

Diamond (in Gold Jewelry)

Carbon (C)

Chert (or Flint)

Chert (cryptocrystalline quartz), SiO2

Emerald (Rough)

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Coquina

Coquina (Biogenic Limestone / CaCO3)

Tektite

Natural impact glass

Quartz geode

Quartz (SiO₂), likely a chalcedony-lined geode with druzy quartz

Dalmatian Stone

Peralkaline Quartz-Feldspar Rock

Polished black stone egg, probably black obsidian

Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements

Granite

Phaneritic Felsic Igneous Rock

Granite

Granite (composed primarily of Quartz, Plagioclase, Alkali Feldspar, and Mica)

Sandstone

Arenite (SiO2 based)

Granite

Granite (Phaneritic intrusive igneous rock; primarily SiO2 and Al2O3)

Sandstone (Quartz-rich)

Arenite