Metamorphic Or Igneous (Context Dependent)

Quartz crystal with Pyrite inclusions

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

Purple cabochon gemstone, likely amethyst or purple sapphire/spinel

Indeterminate from image; possible quartz (SiO₂), corundum (Al₂O₃), or spinel (MgAl₂O₄)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Parti Sapphire

Corundum (Al2O3)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Iron-rich meteorite candidate

Unclassified meteoritic iron–stone material; possible stony-iron meteorite or terrestrial ironstone

Polished orbicular granite heart

Granite, commonly quartz–alkali feldspar–plagioclase–biotite granite; exact locality-dependent

Flint (chert)

Microcrystalline quartz (SiO₂), variety of chert

Quartz / Calcite Vein Rock

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)

Hag Stone

Perforated Sedimentary Rock (typically Sandstone or Siltstone)

Jasper

Agate/Jasper (Microcrystalline Quartz, SiO2)

Mixed rough mineral specimens, likely calcite with prehnite/zeolite

Calcite (CaCO₃), with probable prehnite (Ca₂Al₂Si₃O₁₀(OH)₂) and/or zeolite-group minerals

Likely iron-stained quartz/chalcedony fragment

Quartz (SiO₂), possibly brecciated or partly chalcedonic, with iron-oxide staining

Polished serpentine (likely greenstone)

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

Milky Quartz (Quartz Vein)

Silicon Dioxide (SiO2)

Asphalt (Bituminous Pavement Bit)

Bitumen-bound aggregate (Petrochemical-bound composite)

Red gemstone ring, likely synthetic ruby or red glass

Unidentified red faceted stone; ruby is corundum (Al₂O₃)

Quartz Pebble

Crystalline Silica (SiO2)

Granite cobble

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

Milky Quartz

Silicon Dioxide (SiO2)

Fluorite

Fluorite (Calcium Fluoride, CaF2)

Milky Quartz with inclusions

Silicon Dioxide (SiO2)

Fossil bivalve shell

Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image

Likely black diamond or dark faceted gemstone ring

Uncertain from the photograph; possibly carbon (diamond) or black spinel, set in metal

Polished black-and-gold pebble, likely jasper or iron-rich chert

Microcrystalline quartz (SiO₂), probably jasper/chert with iron-oxide bands

Seashell (Cone Snail Shell)

Conus sp. (Calcium Carbonate, CaCO3)

Sandstone (likely Ferruginous)

Sandstone (SiO2 with iron oxides)

Milky Quartz (Common Quartz)

Quartz (Silicon Dioxide, SiO2)

Calcite (commonly referred to as Orange Calcite or Honey Calcite given its color)

Calcite

Faceted clear gemstone, likely quartz (rock crystal)

Quartz, silicon dioxide (SiO₂); exact identity is uncertain because the strong flash and cut obscure diagnostic features

Ferruginous Sandstone

Ferruginous Sandstone (Quartz Arenite with Iron Oxide cement)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Faceted yellow gemstone ring

Likely yellow sapphire (corundum), but exact identification requires testing; alternatives include citrine, chrysoberyl, or treated diamond.

Red carnelian (polished chalcedony)

Carnelian, microcrystalline quartz (SiO₂), cryptocrystalline variety of chalcedony

Sandstone

Arenite (primarily Quartz Sandstone)

Sodium Polyacrylate (Superabsorbent Polymer)

Sodium Polyacrylate [-CH2-CH(COONa)-]n

Nickel coin (U.S. currency)

Cupronickel (75% Copper, 25% Nickel alloy)

Blue Quartz (or Blue Aventurine)

Silicon Dioxide (SiO2) with inclusions (typically Crocidolite or Dumortierite)

Milky Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Polished turquoise-matrix cabochon

Turquoise, hydrated copper–aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O, with iron-rich matrix and possible chrysocolla

Tumbled orange chalcedony or carnelian

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/carnelian

Limonite/goethite-bearing ironstone (probable)

Goethite, α-FeO(OH), commonly mixed with limonite (hydrated iron oxides) and host rock