Organic Gemstone (Not A Rock)

Chert (Nodule)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Olivine Peridotite

Peridotite (comprising Olivine (Mg,Fe)2SiO4 and Pyroxene)

Granitic Pegmatite

Granite Pegmatite (coarse-grained intrusive igneous rock)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Chert (specifically Yellow/Brown Chert or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Lapis Lazuli

Lapis lazuli (complex rock composed of Lazurite, Calcite, and Pyrite)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Obsidian

Amorphous Volcanic Glass (primarily SiO2)

Chert (and Chert-based Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Unakite

Unakite (Episyenite composition: Feldspar, Epidote, and Quartz)

Fossiliferous Rock (likely Dinosaur Fossil in Matrix)

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

Granatic Pegmatite

Pegmatitic Granite

Blue Quartz (Aventurine)

Silicon Dioxide (SiO2) with fibrous inclusions (commonly Dumortierite)

Milky Quartz

Silicon Dioxide (SiO2)

Unakite

Unakite Lepidolite

Unakite

Epidotized Granite

Clear Quartz (Druzy/Crystal Cluster)

Silicon Dioxide (SiO2)

Unakite

Unakite (Epidotized Granite)

Chert (Chalcedony)

Silicon Dioxide (SiO2)

Olivine in Basalt matrix

Peridotite (Mg, Fe)2SiO4

Chert / Flint

Microcrystalline or cryptocrystalline quartz (SiO2)

Pink Quartzite

Quartzite (SiO2 with minor iron oxide impurities)

Carnelian

Carnelian (a variety of Chalcedony); SiO2 (Silicon Dioxide)

Amber

Succinite

Dalmatian Stone (commonly Dyed)

Dalmatian Jasper (Peralkaline igneous rock)

Chert (Brown Variety)

Silicon dioxide (SiO2)

Agate

Silicon dioxide (SiO2)

Chert (Chalky/Gray Variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Black Opal

Hydrated silica (SiO2·nH2O)

Black Obsidian

Volcanic Glass (SiO2 + impurities)

Labradorite (Larvikite variety)

Plagioclase Feldspar (Na,Ca)(Al,Si)4O8 with Monzonite/Syenite matrix

Unakite

Epidotized Granite

Red Jasper (Quartz)

Silicon Dioxide (SiO2) with Iron impurities

Dalmatian Stone (often called Dalmatian Jasper)

Peralkaline Quartz-Feldspar Rock with Arfvedsonite (formerly believed to be Jasper)

Yellow Quartz (Citrine Quartz variety / Ferruginous Quartz)

Silicon Dioxide (SiO2) with iron inclusions

Greenstone (Epidote/Chlorite-rich Metabasalt)

Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))

Clear Quartz

Silicon Dioxide (SiO2)

Oak-grain Laminate (Industrial/Decorative Furniture Finish)

Melamine Resin-impregnated Decorative Paper on Particleboard (Cellulose/Thermosetting Plastic)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Chert (varietal Flint or Jasper)

Microcrystalline Quartz (SiO2)

Chrysocolla and Azurite in Matrix

Hydrated copper phyllosilicate (Chrysocolla - Cu2H2Si2O5(OH)4) and Copper carbonate (Azurite - Cu3(CO3)2(OH)2)