Mineral Based Composite

Biotite Schist

Biotite Schist (predominantly K(Mg,Fe)3AlSi3O10(OH,F)2)

Labradorite

Plagioclase Feldspar (Na,Ca)(Al,Si)4O8

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Labradorite (Polished Sphere)

Labradorite ((Ca, Na)(Al, Si)4O8)

Heat-Treated Citrine (Amethyst Geode Fragment)

Silicon Dioxide (SiO2) with iron impurities

Biotite (Black Mica)

Biotite - K(Mg,Fe)3(AlSi3O10)(OH)2

Fuchsite

Chromium-bearing Muscovite [K(Al,Cr)2(AlSi3O10)(OH)2]

Mica

Phlogopite or Biotite group (KMg3(AlSi3O10)(F,OH)2 / K(Mg,Fe)3AlSi3O10(OH)2)

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(OH)2

Opal

Hydrated amorphous form of silica (SiO2·nH2O)

Tree Agate

SiO2

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Iron-stained Quartz

Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3/FeO(OH))

Schist

Mica Schist

Porphyritic Basalt

Porphyritic Basalt

Basalt with Plagioclase Phenocrysts

Porphyritic Basalt

Diorite

Diorite (Intermediate Plutonic Rock)

Basalt with Quartz Vein and Weathering Crust

Amygdaloidal or Porphyritic Basalt

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic volcanic rock with secondary mineral fillings)

Pink Granite

Granite (Phaneritic igneous rock rich in Alkali Feldspar)

Amethyst on Agate/Host Rock

Silicon Dioxide (SiO2) with iron impurities

Fire Agate

Silicon Dioxide (SiO2) with layers of Limonite/Goethite

Dyed Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Bloodstone (Heliotrope)

Silicon Dioxide (SiO2) - Variety of Chalcedony/Jasper

Tree Agate (or Moss Agate)

Dendritic Agate (Silicon Dioxide - SiO2)

Labradorite

Labradorite (Ca,Na)(Al,Si)4O8

Granite

Phaneritic Felsic Igneous Rock (primarily Quartz, Alkali Feldspar, and Plagioclase)

Granite

Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)

Sandstone (likely Siltstone)

Arenite or Siltstone (high SiO2 content)

Citrine

SiO2 (Silicon Dioxide)

Granodiorite

Phaneritic Granodiorite

Granite

Granitic intrusive igneous rock

Greenschist (or Serpentinite) with Quartz-Feldspar Vein

Metabasalt / Greenschist Facies Rock

Vesicular basalt

Basalt, typically composed of plagioclase feldspar, pyroxene, and minor olivine or iron oxides

Vesicular Basalt (Lava Rock)

Aphanitic Mafic Igneous Rock

Basalt (Crushed Stone Aggregate)

Mafic Volcanic Basalt (Major Minerals: Plagioclase Feldspar, Pyroxene, Olivine)

Tree Agate

Silicon Dioxide with Chlorite inclusions (SiO2)

Red Sandstone

Arenite (primarily composed of SiO2 with Fe2O3 cement)

Basalt

Aphanitic Mafic Igneous Rock

Diorite (possibly Orbicular Diorite or Porphyritic Diorite)

Intermediate Phaneritic Igneous Rock

Gneiss (Granitic Gneiss)

Gneiss (from German Gneis, related to 'spark')

Granodiorite

Granodiorite (Quartz + Plagioclase + Alkali Feldspar + Biotite/Hornblende)