Organic Gemstone (Often Associated With Sedimentary Sequences)

Chert (Quartz Variety)

Chert (Silicon Dioxide, SiO2)

Moonstone

Adularia (orthoclase) or Albite (plagioclase), a feldspar mineral (KAlSi3O8 or NaAlSi3O8 respectively, often a mixture)

Shale

Shale (clastic sedimentary rock)

Jasper

Silicon dioxide (SiO2)

Fossiliferous Limestone (Crinoidal)

Calcite-bearing bioclastic packstone (CaCO3)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint or Jasper depending on color)

Chert (SiO2 - Microcrystalline or Cryptocrystalline Quartz)

Chalk

Calcium Carbonate (CaCO3)

Jasper

Jasper (Silicon Dioxide, SiO2)

Red Jasper

Silicon Dioxide with Iron inclusions (SiO2)

Chert (and/or Siltstone River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Rhodonite

Rhodonite (Manganese silicate), (Mn,Fe,Mg,Ca)SiO3

Jasper (Petrified Wood variant)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Stromatolite (Jasper-replaced)

Fossilized Stromatolite (Cyanobacteria / Cryptozon / Silica SiO2)

Chert (Flint Pebbles)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Green Jasper

Jasper (Silicon Dioxide, SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Chert (specifically a stream-worn Chert Nodule)

Sedimentary Cryptocrystalline Quartz (SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Chert (Jasper/Iron-stained Quartzite)

Silicon Dioxide (SiO2)

Chert (Smooth River Pebble)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fossilized Horn Coral

Order Rugosa (Rugose Coral)

Clear Quartz

Silicon Dioxide (SiO2)

Citrine

Quartz (SiO2) - specifically, a variety of macrocrystalline quartz

Chert (Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (variations include Flint/Jasper)

Cryptocrystalline Silicon Dioxide (SiO2)

Polished Rhodonite Obelisk

Rhodonite (Manganese Iron Magnesium Calcium Silicate) - (Mn,Fe,Mg,Ca)SiO3

Chert (Flint)

Microcrystalline or cryptocrystalline quartz (SiO2)

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide and organic impurities

Chert (often called Flint)

Microcrystalline to cryptocrystalline quartz (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Carnelian

Carnelian (Silicon Dioxide - SiO2)

Chert (White-Tan variety)

Silicon dioxide (SiO2) / Microcrystalline Quartz

Petrified Wood

Silicified Wood (primarily SiO2)

Picture Jasper

Silicon Dioxide (SiO2) - Opaque Chert/Quartzite variety

Red Sandstone (Siltstone/Mudstone variety)

Ferruginous Sandstone (composed primarily of Quartz with Hematite cementation)

Lapis Lazuli

Lapis Lazuli (a rock composed primarily of Lazurite, Sodalite, Calcite, and Pyrite)

Jasper

Jasper (Silicified microcrystalline quartz) - SiO2

Almandine Garnet in Matrix

Almandine (Fe3Al2(SiO4)3)

Chert (often called Flint)

Cryptocrystalline Quartz (SiO2)

Chert

Chert (microcrystalline quartz)