Organic (Geological Relative)

Bismuth

Bismuth (Bi)

Lapis Lazuli

Lapis Lazuli (a rock composed primarily of Lazurite (Na,Ca)₈[(S,Cl,SO₄,OH)₂|(Al₆Si₆O₂₄)], with varying amounts of Calcite, Pyrite, and Sodalite.)

Quartzite Pebble

Metamorphic Quartzite (SiO2)

Chert

Microcrystalline quartz (SiO2)

Granite

Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase Feldspar)

Chert (often referred to as Flint or Jasper when pigmented)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz / Quartzite

Silicon Dioxide (SiO2)

Chert (with Fossiliferous Silicification)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Gravel)

Chert (Cryptocrystalline silicon dioxide, SiO2)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Granite

Phaneritic plutonic rock (composed of Quartz, Feldspar, and Mica/Amphibole)

Chert

Microcrystalline quartz (SiO2)

Pegmatite

Igneous Pegmatite

Chert

Microcrystalline quartz (SiO2)

Quartzite

Metamorphic Quartz-rich Rock

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Granite

Phaneritic plutonic rock (primarily Quartz, Alkali Feldspar, and Plagioclase)

Blue Calcite

Calcium Carbonate (CaCO3)

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

Chert (with Iron Staining)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Likely serpentine (serpentinite) pebbles

Serpentine-group minerals, chiefly antigorite, lizardite, and/or chrysotile; commonly Mg₃Si₂O₅(OH)₄, sometimes containing magnetite, chromite, and minor carbonate minerals

Bauxite Ore

Hydrated aluminum oxides (e.g., Gibbsite Al(OH)3, Boehmite ̲̲̲̲AlOOH, Diaspore ̲̲̲̲AlOOH)

Basalt with Weathered Surface

Basalt

Azurite-Malachite (often a mixed specimen)

Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2(CO3)(OH)2. The specimen appears to be a natural mixture or intergrowth of these two minerals.

Topaz

Topaz (Al2SiO4(F,OH)2)

Green Aventurine

Aventurine Quartz (SiO2 with fuchsite inclusions)

Limestone

Calcium Carbonate (CaCO3)

Polished Mookaite Jasper

SiO2 (Silicon Dioxide with impurities)

Chert (White Flint)

Silicon Dioxide (SiO2)

Granite (Pink/Potassium-rich)

Pink Granite (contains K-Feldspar, Quartz, and Plagioclase)

Chert (within Limestone)

Silicon Dioxide (SiO2)

Pink Granite

Granite (composed primarily of Orthoclase Felspar, Quartz, and Plagioclase)

Chert

Microcrystalline Quartz (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Quartzite

Quartzite (SiO2)

Schist

Mica Schist

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Orthoclase Feldspar (or K-Feldspar)

Orthoclase (KAlSi3O8)

Beryl (Variety Mix)

Be3Al2(Si6O18)