Organic Gemstone (Sedimentary Classification)

Carnelian Agate

Silicon Dioxide with Hematite impurities (SiO2 + Fe2O3)

Milky Quartz

Quartz (Silica / Silicon Dioxide), SiO2

Kyanite

Kyanite (Al2SiO5)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Chert (varietal known as Jasper or Flint)

Silicon Dioxide (SiO2)

Sedimentary Rock

Fluorite

Calcium Fluoride (CaF2)

Epidote

Epidote Group (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Carnelian

Cryptocrystalline Quartz (SiO2 with iron oxide impurities)

Chert (specifically Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pearl

Calcium Carbonate (primarily Aragonite and Calcite), CaCO3

Clear Quartz

Silicon Dioxide (SiO2)

Chalcedony (Agatized Coral / Rough Chalcedony Node)

Silicon Dioxide (SiO2)

Shungite

Non-crystalline carbon (similar to anthracite coal or meta-anthracite)

Anthracite Coal

Anthracite

Mineral (variety of Chalcedony)

Quartz

Silicon Dioxide (SiO₂)

Mineral

Carnelian

Carnelian (a variety of Chalcedony, which is a microcrystalline quartz, SiO2)

Chert (Jasper/Carnelian variety)

Microcrystalline Quartz (SiO2)

Carnelian Agate/Jasper blend

Silicon Dioxide (SiO2) - variety of Chalcedony

Blue Kyanite

Kyanite (Al2SiO5)

Turquoise with Pyrite

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O] with Iron Pyrite (FeS2)

Chalcedony (Yellow Agate/Chert)

Silicon Dioxide (SiO2)

Fluorite

Calcium Fluoride (CaF2)

Red Jasper

Silicon Dioxide (SiO₂)

Quartz (Microcrystalline/Chert)

Silicon Dioxide (SiO2)

Apatite

Fluorapatite, Chlorapatite, and Hydroxylapatite (Ca5(PO4)3(F,Cl,OH))

Carnelian (a variety of Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Turquoise

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

Petrified Wood

Silicified Wood (SiO2)

Fluorite and Red Jasper

Fluorite (Calcium Fluoride, CaF2) and Red Jasper (Silicon Dioxide, SiO2)

Turquoise and Hematite

CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Fe2O3 (Hematite)

Chalcedony (specifically Agate or Carnelian pebble)

Chalcedony (Microcrystalline Quartz, SiO2)

Banded Agate

Cryptocrystalline Quartz (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Carnelian

Silicon dioxide (SiO2) with Iron Oxide impurities (Fe2O3)

Petrified Wood

Silicified Wood (SiO2)

Agatized Petrified Wood

Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood

Turquoise and Hematite

Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Hematite (Fe2O3)