Synthetic Polymer (Polylactic Acid)

Yellow Calcite

Calcium Carbonate (CaCO3)

Coquina

Bioclastic Limestone

Botryoidal Aragonite (Cave Popcorn)

Aragonite (Calcium Carbonate, CaCO3)

Orange Calcite Sphere

Calcium Carbonate (CaCO3)

Limestone (specifically fossiliferous/skeletal limestone)

Calcium Carbonate (CaCO3)

Malachite Coating on Host Rock

Malachite [Cu2CO3(OH)2]

Limestone

Calcareous Sedimentary Rock (CaCO3)

Limestone with Calcite Crystals

Calcium Carbonate (CaCO3)

Quartzite with vugs/druzy quartz

Crystalline Silicon Dioxide (SiO2)

Coprolite

Fossilized Feces

Bornite

Copper Iron Sulfide (Cu5FeS4)

Quartzite

Quartzite (primarily Silicon Dioxide, SiO2)

Bornite (Peacock Ore)

Bornite (Cu5FeS4)

Calcite (likely a tumbled specimen)

Calcite (CaCO 3 )

Bornite

Bornite (Cu5FeS4)

Peacock Ore

Bornite (Cu5FeS4)

Baltic Amber

Succinite (Polmerized conifer resin)

Black Onyx

Silicon Dioxide (SiO2) with cryptocrystalline structure

Green Onyx (Banded Calcite)

Travertine (CaCO3 - Calcium Carbonate)

Calcite

Calcium Carbonate (CaCO3)

Green Fluorite

Calcium Fluoride (CaF2)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Green Fluorite

Fluorite (Calcium Fluoride, CaF2)

Fluorite (Rainbow Fluorite)

Calcium Fluoride (CaF2)

Pyrite (Cube variety)

Iron Sulfide (FeS2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Pyrite (Iron Pyrite)

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Pyrite in Shale

Iron Disulfide (FeS2) in Sedimentary Shale

Fluorite

Calcium Fluoride (CaF2)

Fluorite

Calcium Fluoride (CaF2)

Pyrite

Iron Disulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Fluorite (Green Fluorite)

Calcium Fluoride (CaF2)

Pyrite

Iron Sulfide (FeS2)

Pyrite (Fool's Gold) Ore

Iron Disulfide (FeS2)

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium) - CuAl6(PO4)4(OH)8·4H2O

Blue Celestite (Celestine)

Strontium sulfate (SrSO4)

Pyrite

Iron Disulfide (FeS2)