Man Made Object (Coin)

Painted River Rock (likely Quartzite or Granite)

Quartzite or Granitic Gneiss (painted)

Siltstone or Limestone Beach Pebble

Siltstone / Micritic Limestone

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

River Pebble (likely Quartzite or Siltstone)

Sedimentary Clast (SiO2 based)

Chondrite Meteorite

Stony Meteorite (Chondrite)

Pearls (likely freshwater cultured pearls)

Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin

Petrified Wood

Silicified Wood (primarily SiO2)

Terrazzo (with Marble and Granite fragments)

Cementitious or resinous composite containing Calcium Carbonate (CaCO3) and Silicates

Amber (Black)

Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)

Banded agate pendant (likely carnelian or brown-and-white chalcedony agate)

Agate, a banded variety of chalcedony; microcrystalline quartz, SiO₂, with iron-oxide coloration

Calcite

Calcite (CaCO₃, Calcium Carbonate)

Cobalt Glass Slug (Man-made Glass)

Amorphous Silica with Cobalt Oxide (SiO2 + CoO)

Gemstone bead necklace (likely citrine or yellow quartz)

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

Blue opalite (often sold as synthetic opal)

Opalite glass; amorphous hydrated silica if natural opal (SiO₂·nH₂O)

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

Ambergris

Ambrein-rich Calculus

Cullet Glass (Man-made Glass Slag)

Amorphous Silica (SiO2) with chemical additives

Pink quartz crystal, possibly rose quartz

Quartz (silicon dioxide, SiO₂), likely pink quartz/rose quartz

Native Silver

Silver (elemental Ag)

Tumbled dark blue-green stone, likely labradorite or indigo gabbro

Indeterminate; possible feldspar-rich labradorite (plagioclase, NaAlSi₃O₈–CaAl₂Si₂O₈)

Small rounded pebble

Unidentified lithic clast; likely fine-grained sandstone, mudstone, or basalt

Polished citrine quartz point

Quartz, silicon dioxide (SiO₂), yellow-orange variety commonly sold as citrine; possibly heat-treated amethyst

Spiny Oyster Shell

Spondylus varians (Biogenic Calcium Carbonate)

Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Undetermined Due to Blur (Possible Flesh-Tone Mineral)

Unknown (Insufficient Visual Clarity)

Orange Calcite

Calcium Carbonate (CaCO3)

Fired Clay Brick (Anthropic Rock substitute)

Anthropogenic polycrystalline ceramic (predominantly Mullite and Quartz: Al6Si2O13 + SiO2)

Tanzanite

Blue Zoisite (Ca2Al3(SiO4)(Si2O7)O(OH))

Black-and-copper polished granite

Biotite granite, likely a commercial gabbro/granite variety

Sea Glass (Frosted Glass)

Amorphous Silica (SiO2) with various metal oxide impurities

Man-made Green Quartz (Lab-grown or Treated)

Silicon Dioxide (SiO2) with artificial coloration

Tumbled blue stone, likely blue aventurine or dyed quartzite

Quartz (SiO₂), likely with inclusions or artificial dye; exact identification requires testing

Heart-shaped Pebble (Limestone/Quartz)

Calcium Carbonate (CaCO3) / Silicon Dioxide (SiO2)

Unable to Identify (Image Obscured)

Diamond (in a gold ring)

Diamond (pure carbon, C)

Cupronickel Coin

Copper-Nickel Alloy (typically 75% Cu, 25% Ni)

Polished mahogany obsidian

Volcanic glass (mostly SiO₂), commonly called mahogany obsidian

Optical Calcite

Calcite (Calcium Carbonate, CaCO3)

Copper Bullion Round

Native Copper (refined), Cu

Weathered limestone pebble

Limestone, chiefly calcite (CaCO₃)

Petrified Wood

Silicified wood (primarily SiO2)