Organic Gemstone (Often Associated With Sedimentary Sequences)

Pyrulite (Pyrite / Chalcopyrite)

Iron Sulfide (FeS2) or Copper Iron Sulfide (CuFeS2)

Fossiliferous Rock (likely Dinosaur Fossil in Matrix)

Permineralized Vertebrate Fossil (Calcium Carbonate/Silica replaced bone material)

Petrified Wood

Silicified Wood (primarily SiO2)

Tourmaline crystal

Tourmaline Group (Complex Borosilicate)

Citrine

Silicon Dioxide (Quartz variety), SiO2

Petrified Wood

Silicified Wood (SiO2)

Rhodochrosite

Manganese carbonate (MnCO3)

Chert (Arrowhead Fragment)

Microcrystalline Quartz (SiO2)

Chert (and Flint)

Microcrystalline Silica (SiO2)

Ruby in Fuchsite

Corundum (Al2O3) in Fuchsite (K(Al,Cr)3Si3O10(OH)2)

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Almandine Garnet in Matrix

Almandine (Fe3Al2(SiO4)3)

Quartz

Silicon Dioxide (SiO2)

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Septarian Nodule

Septarian Concretion (CaCO3 with Siderite/Limonite streaks)

Unakite (Epidote and Feldspar)

Unakite (modified granite composed of Epidote Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) and Orthoclase KAlSi3O8)

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with Bioclasts

Tiger's Eye

Tiger's Eye (a variety of Quartz, SiO₂)

Carnelian

Silicon Dioxide (Quartz variety, SiO2)

Banded Chert (or River Jasper)

Microcrystalline Quartz (SiO2) with iron oxide impurities

Orange Calcite

Calcium Carbonate (CaCO3)

Chert (Tan/Buff Chert)

Microcrystalline Quartz (SiO2)

Green Sandstone

Glauconitic Sandstone

Chert (or Flint)

Chert (microcrystalline or cryptocrystalline quartz, SiO2)

Chert (Chalky/Gray Variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Moonstone

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

Jasper and Chert Conglomerate

Ferruginous Microcrystalline Quartz (SiO2)

Amber / Copal

Fossilized Tree Resin (Succinate)

Shale

Laminated Fissile Pelite

Jasper

Silicon Dioxide (Microcrystalline Quartz, SiO2)

Red Jasper

Silicon dioxide with iron oxide inclusions (SiO2 + Fe2O3)

Carnelian

Carnelian (SiO2 variant)

Fluorite

Calcium Fluoride (CaF2)

Black Onyx

Chalcedony (SiO2)

Asphalt / Bituminous Aggregate

Bituminous mixture (Hydrocarbon-based sediment)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Chert (specifically Gray/Black Chert)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Rhodonite

Manganese Inosilicate (MnSiO3)

Quartz

Silicon Dioxide (SiO2)

Amber

Fossilized Tree Resin (C10H16O)

Graphite

Graphite (C)

Quartzite

Quartzite (primarily SiO2)