Synthetic Polymer (Polylactic Acid)

Chert (White Flint)

Microcrystalline Quartz (SiO2)

Chert Nodule in Limestone

Chert (Microcrystalline Quartz, SiO2) and Limestone (Calcium Carbonate, CaCO3)

Tufa

Calcareous Tufa (CaCO3)

Oolitic Limestone / Fossiliferous Chert

Oolitic Limestone (CaCO3) / Silicified Limestone

Calcite (Iceland Spar)

Calcite (Calcium Carbonate, CaCO3)

Orange Calcite

Calcite (Calcium Carbonate - CaCO3)

Limestone

Sedimentary rock composed of Calcium Carbonate (CaCO3)

Blue Calcite

Calcium Carbonate (CaCO3)

Iridium sand or Osmium-Iridium nugget

Iridosmine / Osmiridium (Platinoid grouping)

Granite

Intrusive Igneous Rock (composed primarily of Quartz: SiO2, Feldspar: KAlSi3O8, and Mica: KAl2(AlSi3O10)(OH)2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Quartzite Cobble

Meta-quartzite (SiO2)

Banded Calcite (known as Mexican Onyx or Calcite Alabaster)

Calcium Carbonate (CaCO3)

Granite (with alteration)

Granite (Felsic intrusive igneous rock)

Turquoise (Green variety)

Hydrous phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Turquoise in Matrix

Hydrous phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O

Turquoise in Matrix

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

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Crushed Limestone

Calcium Carbonate (CaCO3)

Banded Calcite (Mexican Onyx)

Calcium Carbonate (CaCO3)

Limestone with Bitumen/Chert

Calcite (CaCO3) containing organic hydrocarbons

Coquina (Limestone)

Bioclastic Limestone (CaCO3)

Green Calcite

Calcium Carbonate (CaCO3)

Quartzite (Tumbled Pebble)

Metamorphosed Quartz Sandstone (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Marble (Carrara Marble style)

Recrystallized Calcite (CaCO3)

Quartzite

Quartzite (primarily SiO2)

Limestone

Calcium Carbonate (CaCO3)

Orange Calcite

Calcium Carbonate (CaCO3)

Quartzite

Quartzite (primarily SiO2)

Quartzite Pebble

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Rock (Mainly SiO2)

Basalt with Calcite Veining

Aphanitic Mafic Igneous Rock (Basalt) with CaCO3

Green Quartzite

Quartzite (primarily SiO2 with trace impurities)

Quartzite

Quartzite (mainly SiO2)

Red Sandstone

Arenite (primarily Quartz with Hematite cement)

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with fossil inclusions

Limestone

Calcium Carbonate (CaCO3)

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Pink Coral

Corallium rubrum (Calcium Carbonate, CaCO3)