Igneous, Sedimentary, Or Metamorphic (Mineral Based)

Gneiss

High-grade Metamorphic Gneiss

Mica Schist

Muscovite Schist (KAl2(AlSi3O10)(OH)2)

Coarse Sand Grain / Lithic Fragment

Clastic Sediment (Lithic fragment or Quartz/Feldspar grain)

Granitoid (Granite/Gneiss)

Granitoid silicate rock, primarily quartz and feldspar

Pearl

Calcium Carbonate (CaCO3) + Conchiolin

Quartz Vein in Sandstone

Sandstone with Hydrothermal Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Healer's Gold (Pyrite and Magnetite in Schist)

Magnetite (Fe3O4) and Pyrite (FeS2) in Mica Schist

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Clear Quartz Crystal

Quartz (Silicon Dioxide, SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Peach/Orange variety)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Clear Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Calcite

Calcium Carbonate (CaCO3)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Banded Gneiss

Gneiss (complex metamorphic silicate rock)

Gneiss (Banded Gneiss)

Gneiss

Mica Schist with Garnet

Garnetiferous Mica Schist

Schist

Mica Schist (Variable chemistry, often rich in muscovite and biotite)

Gastropod Steinkern (Fossil Snail Internal Mold)

Class Gastropoda (Internal Mold)

Gneiss (River Cobble)

Gneiss (Foliated Metamorphic Rock)

Conglomerate

Conglomerate (Clastic Sedimentary Rock)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Milky/Common variant)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Magnetite / Ironstone

Magnetite (Fe3O4)

Milky Quartz

Silicon Dioxide (SiO2)

Gneiss

Gneiss (Metamorphic high-grade)

Opal

Hydrated silica (SiO2·nH2O)

Mica Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Gneiss

Gneiss

Gneiss (specifically a water-worn pebble)

Gneiss

Gneiss

Gneiss (High-grade Metamorphic Rock)

Quartz (Milky/Vein Quartz)

Silicon Dioxide (SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Hematite

Iron(III) oxide (Fe2O3)

Dalmatian Stone (Dalmatian Jasper)

Dalmatian Stone (A variety of Perthite / Aplite)

Asphalt (Bituminous Concrete)

Bituminous mix containing aggregates and petroleum-based binder (CnH2n+2)