Crystal

Amethyst crystal point

Quartz, purple variety — silicon dioxide (SiO₂)

Quartz geode (likely amethyst-bearing)

Silica geode; quartz, SiO₂, with possible amethyst and minor iron oxides

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Raw Emerald in Matrix

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Green Tourmaline

Verdelite (Silicate mineral); Na(Li,Al)3Al6(BO3)3Si6O18(OH)4

Milky quartz (rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

Raw greenish crystal/mineral fragment

Uncertain from image; possibly olivine (forsterite-rich), epidote, or green tourmaline

Milky quartz (rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

Quartz Druzy / Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Obsidian

Volcanic Glass (comprised primarily of SiO2)

Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Basalt with Plagioclase Phenocryst

Porphyritic Basalt

Muscovite mica (mica crystal)

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

Snowflake Obsidian

Volcanic Glass with Spherulite inclusions (SiO2)

Porphyritic Andesite

Andesite with Hornblende phenocrysts

Snowflake Obsidian

Volcanic Glass (spherulitic obsidian)

Mahogany Obsidian

Volcanic Glass (SiO2 with iron and magnesium oxides)

Tourmalinated quartz crystal point

Quartz (SiO₂) with black tourmaline (schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄) inclusions

Rough quartz crystal cluster

Quartz (silicon dioxide, SiO₂), likely milky or included quartz

Rough Diamond (or Quartz Crystal)

Carbon (C) [if Diamond] / Silicon Dioxide (SiO2) [if Quartz]

Quartz Crystal with Inclusions

Silicon Dioxide (SiO2)

Blue-green fluorite crystal

Fluorite (calcium fluoride, CaF₂)

Garnet (Rough Almandine Crystal)

Almandine Garnet (Fe3Al2(SiO4)3)

Rough Diamond (Uncut Diamond)

Native Carbon (C)

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Halite

Sodium chloride (NaCl)

Sulfur on Aragonite

Sulfur (S) on Aragonite (CaCO3)

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Small pale pink crystal, possibly rose quartz or morganite

Quartz (SiO₂), or beryl (Be₃Al₂Si₆O₁₈) if morganite

Quartz (Clear Quartz / Rock Crystal)

Silicon Dioxide (SiO2)

White Quartz Star-cut crystal

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Tumbled and polished quartz crystal points

Quartz (silicon dioxide, SiO₂), chiefly rock crystal with smoky or included varieties

Limestone with Calcite Vug

Calcium Carbonate (CaCO3) in Sedimentary Matrix

Pyrite Concretion

Iron Sulfide (FeS2) in Sedimentary Matrix

Calcite crystal cluster

Calcite (calcium carbonate, CaCO₃), likely on a carbonate matrix

Iridescent bismuth crystal

Bismuth (Bi), commonly laboratory-grown and oxide-coated