Sedimentary (Artificial)

Milky Quartz (Druzy Geode fragment)

Silicon Dioxide (SiO2)

Brachiopod Fossil (Spiriferid)

Order Spiriferida (Phylum Brachiopoda); mineralized as Calcite (CaCO3) or Chert (SiO2)

Limestone (Cliff Formation)

Limestone (predominantly CaCO3 as calcite)

Banded Iron Formation (BIF)

Banded Iron Formation

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity

Amber (Copal)

Fossilized Tree Resin (C10H16O)

Epidote-bearing Granite (Unakite-like)

Epidotized Granite

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Chert (or Flint)

Chert (cryptocrystalline quartz), SiO2

Quartzite

Quartzite (primarily SiO2)

Banded Agate (specifically Carnelian Agate)

Silicon Dioxide (SiO2)

Satin Spar Selenite

Satin Spar (Calcium Sulfate Dihydrate, CaSO4·2H2O)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Amber

Succinite

Satin Spar Selenite

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Orange Calcite

Calcium Carbonate (CaCO3)

Garnet

Almandine (Fe3Al2(SiO4)3)

Chert (Flint)

Chert (SiO2)

Quartz

Silicon Dioxide (SiO2)

Carnelian

Silicon dioxide / Chalcedony (SiO2)

Chert

Chert (SiO2)

Botryoidal Chalcedony

Silicon Dioxide (SiO2)

Turquoise (likely stabilized or simulated Howlite)

CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Amber

Succinate (Organic Fossilized Resin)

Chert (Flint/Jasper variety)

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Quartz (Milky or Clear fragment)

Silicon Dioxide (SiO2)

Chert (and Limestone)

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)

Quartz

Silicon Dioxide (SiO2)

Quartz Crystal Fragment

Quartz (Silicon Dioxide, SiO2)

Clear Quartz Crystal

Quartz (Silicon Dioxide - SiO2)

Quartz (Milky/Crystalline fragment)

Silicon Dioxide (SiO2)

Gneiss

High-grade Metamorphic Gneiss

Quartz

Silicon dioxide (SiO2)

Quartz (Small Pebble)

Silicon Dioxide (SiO2)

Carnelian (Red Agate)

Silicon dioxide (SiO2) with iron oxide impurities

Yellow Jasper

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Orthoclase Feldspar

KAlSi3O8 (Potassium Aluminum Silicate)