Mineral (Tectosilicate)

Agate (specifically Waterline or Onyx-type Agate)

Silicon Dioxide (SiO2) - variety Chalcedony

Beryl (likely Aquamarine or Green Beryl)

Beryllium aluminum silicate (Be3Al2Si6O18)

Tourmalinated Quartz

SiO2 with NaFe3+3Al6(BO3)3Si6O18(OH)4 inclusions

Greenschist / Chloritaform Schist

Chlorite Schist (Group of Silicate Minerals)

Fossilized Shark Tooth (Fragment) in Matrix

Elasmobranchii (subclass)

Dinosaur Bone (Fossilized)

Permineralized Bone (CaCO3 or SiO2 after Hydroxylapatite)

Aventurine

Aventurine Quartz (SiO2 with inclusions)

Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Blue Quartz (Dumortierite Quartz)

SiO2 containing inclusions of Dumortierite [Al7(BO3)(SiO4)3O3]

Greenstone (Epidote/Chlorite-rich Metabasalt)

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

Granite

Granite (silica-rich intrusive igneous rock)

Fuchsite

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Gneiss

Gneiss

Red Sandstone

Arenite (Iron-rich)

Greenschist

Greenschist (composed of Chlorite, Actinolite, and Epidote)

Turquoise (possible Howlite imitation)

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

Sandstone

Arenite (mainly SiO2 with varying cements)

Sandstone

Arenite

Quartz Geode

Silicon Dioxide (SiO2)

Variscite (or potentially a turquoise/variscite matrix cabochon, or an impression jasper)

AlPO4·2H2O (Variscite) or related phosphate/silicate material depending on exact composition

Howlite and Purpurite druzy

Calcium Borosilicate Hydroxide (Howlite) and Manganese Phosphate (Purpurite)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Tumbled Moonstone

Feldspar (Orthoclase/Albite), KAlSi3O8

Sandstone

Arenite (primarily SiO2)

Turquoise

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

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Quartz Geode

Silicon Dioxide (SiO2)

Quartz Geode

Quartz (Silicon Dioxide, SiO2) in a Geode

Satin Spar (Satin Spar Selenite)

Gypsum (CaSO4·2H2O)

Satin Spar (often sold as Selenite)

Gypsum (CaSO4·2H2O)

Sandstone

Arenite (SiO2 primarily)

Schist

Mica Schist (primarily Muscovite and Biotite)

Red Vanadinite on Matrix

Vanadinite (Pb5(VO4)3Cl)

Gneiss

Gneiss (a type of metamorphic rock)

Blue Calcite

Calcium Carbonate (CaCO3)

Pink Granite

Felsic Plutonic Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Shark Tooth Fossil

Elasmobranchii dentition (fossilized)

Sandstone Beach Pebble

Clastic sedimentary rock (SiO2 with iron oxide cement)

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Diamond

Diamond (Pure Carbon - C)

Diamond

Diamond (C)

Diamond

Carbon (C)