Industrial Byproduct (Often Mistaken For Obsidian Or Mineral)

Orange Calcite

Calcium Carbonate (CaCO3)

Quartz (vein quartz)

SiO2 (Silicon Dioxide)

Fluorite (Purple Fluorite in Matrix)

Fluorite (Calcium Fluoride, CaF2)

Blue Calcite

Calcite (Calcium Carbonate, CaCO3)

Dyed Magnesite (often sold as Red Turquoise or Howlite)

Magnesium Carbonate (MgCO3)

Schist

Mica Schist (Medium-grade Metamorphic Rock)

Fluorite (Rainbow Fluorite)

Calcium Fluoride (CaF2)

Magnetite (Lodestone)

Magnetite (Fe3O4)

Quartz Pebbles

Silicon Dioxide (SiO2)

Quartz (likely Milky Quartz)

Quartz (SiO₂ - Silicon Dioxide)

Banded Agate

Cryptocrystalline Quartz (SiO2)

Granite

Phaneritic Igneous Rock (composed mostly of Quartz, Feldspar, and Mica)

Quartzite with Dark Mineral Inclusions

Quartzite (primarily SiO2) with accessory minerals

Ferruginous Quartz

SiO2 (Silicon Dioxide) with Iron Oxide inclusions (FeO(OH) / Fe2O3)

Oolitic Ironstone

Sedimentary Ooidal Ironstone (Limonite/Hematite mixture)

Almandine Garnet

Fe3Al2(SiO4)3

Blue Goldstone

Synthetic Avanturine Glass (or Aventurine Glass)

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2)

Ring with an Orange Inlay

N/A (Man-made object)

Banded Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Banded Calcite (often sold as 'Green Onyx')

Calcite (Calcium Carbonate, CaCO3)

Granitic Pegmatite with Schorl

Granitic Pegmatite (NaAlSi3O8, KAlSi3O8, SiO2) with Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

Rose Quartz

Silicon dioxide (SiO2)

Quartz Druze on Matrix (Geode Fragment)

Quartz (Silicon Dioxide, SiO2)

Diamond (Green tinted)

Carbon (C) with trace impurities or lattice defects

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Flesh-colored Quartzite

Quartzite (SiO2)

Amethyst

Quartz (SiO2) variety

Quartzite Pebble

Quartzite (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Basalt

Mafic volcanic rock (dominated by Plagioclase and Pyroxene)

Quartzite Cobble

Quartzite (mostly SiO2)

Green Agate

Silicon dioxide (SiO₂)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Agate (Grey Agate Slice)

Microcrystalline Quartz (SiO2)

Orange Calcite (often commercially sold as Honey Calcite or Aragonite)

Calcium Carbonate (CaCO3)

Grey Chalcedony (Agate)

Silicon Dioxide (SiO2)

Bog Iron (Limonite Concretion)

Limonite (FeO(OH)·nH2O)

Tourmaline (likely Schorl)

Tourmaline Group Mineral (e.g., Schorl for black varieties); (Na,Ca)(Li,Mg,Fe,Mn,Al)3Al6(BO3)3Si6O18(OH)4

Smoky Quartz (with inclusions)

Silicon Dioxide (SiO2)

Diamond

Diamond (a metastable allotrope of carbon, C)

Mica Schist

Crystalline Schist (often primarily Muscovite or Biotite sheet silicates)