Mineral And Metamorphic Rock

Anthracite Coal

Anthracite (Carbon-rich metamorphic rock)

Quartzite Cobble

Metamorphic Quartz-rich Rock (SiO2)

Slate

Phyllo-silicate based metamorphic rock

Anthracite Coal

Low-grade metamorphic carbonaceous rock

Anthracite Coal

Anthracite (Carbon-rich metamorphic rock)

Gneiss

High-grade foliated metamorphic rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

Labradorite

Labradorite (a variety of Plagioclase Feldspar), Na(AlSi3O8) to Ca(Al2Si2O8)

Clear quartz crystal point

Quartz (silicon dioxide, SiO₂), likely a polished or cut crystal

Quartz (vein quartz)

SiO2 (Silicon Dioxide)

Quartzite

Metamorphic rock predominantly composed of Quartz (SiO2)

Unakite Jasper

Epidotized Granite

Petrified Wood

Silicified Wood (primarily Quartz / Chalcedony: SiO2)

Quartzite (River Pebble)

Quartzite (composed primarily of Silica, SiO2)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)

Pyrite-bearing rock (likely pyrite in a quartz or sulfide-rich matrix)

Pyrite, FeS₂; the gray host may be quartz, carbonate, or another sulfide-bearing rock

Green Opal

Hydrated Silica (SiO2·nH2O)

Diamond

Carbon (C)

Diamond

Carbon (C)

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals: (Mg,Fe)3Si2O5(OH)4)

Quartz

Quartz (SiO₂)

Sandstone (Feldspathic / Arkose)

Sandstone (SiO2 with variable mineral grains)

Pink Marble

Recrystallized Limestone (Calcium Carbonate, CaCO3)

Anthracite Coal

Anthracite (Carbon Content: 86%-97%)

Granitoid Gneiss with Feldspar Vein

Gneiss (High-grade Metamorphic Rock) with Potassium Feldspar (KAlSi3O8)

Agate

Silicon Dioxide (Chalcedony), SiO2

Serpentine / Serpentinite (with Weathering Crust)

Serpentinite (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4

Black Tourmaline (Schorl)

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

Greenstone (Prase / Metavolcanic)

Metamorphosed volcanic rock (Greenstone)

Unakite

Epidotized Granite

Quartzite Cobble

Metamorphic rock primarily composed of Quartz (SiO2)

Glacial Cobbles (predominantly Granite and Gneiss)

Mixed lithologies (Quartz, Feldspar, Mica assemblage)

Crushed Granite and Basalt

Phaneritic Igneous Rock / Aphanitic Igneous Rock

Gravel

Unconsolidated rock fragments / detrital sediment

Hematite

Iron(III) oxide (Fe2O3)

Quartzite

Quartzite

Unakite

Epidotized Granite

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Druzy Quartz on Limestone

Silicon Dioxide (SiO2) on Calcium Carbonate (CaCO3)

Mixed Gemstone Bracelet

Mixed natural minerals and rocks (e.g., Rhodonite, Malachite, Sodalite, Rose Quartz, Black Tourmaline, Quartz/Chalcedony variants)

Kyanite

Kyanite (Al2SiO5)

Sapphire (Raw/Rough)

Corundum (Al2O3)