Metamorphic Or Igneous (Context Dependent)

Shungite

Non-crystalline carbon (high-carbon metamorphic rock)

Coal (Anthracite)

Anthracite (Carbon-based organic sedimentary/metamorphic rock)

Quartzite with Iron Inclusions

Metamorphic Silicon Dioxide (SiO2) with impure Limonite/Hematite

Mica Schist

Medium-grade regional metamorphic rock (composition varies)

Slate

Metamorphosed Shale (Fine-grained Foliated Metamorphic Rock)

Fuchsite Schist

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

Yellow Quartzite

Quartzite (primarily Silicon Dioxide - SiO2)

Green Aventurine

Aventurine Quartz (SiO2 with inclusions of Fuchsite)

Tiffany Stone

Bertrandite Fluorite (CaF2 + Be4Si2O7(OH)2)

Red Quartzite River Stone

Quartzite (SiO2)

Schist

Mica Schist

Yellow Aventurine (or Citrine-colored Quartz)

Silicon Dioxide (SiO2) with inclusions

Quartzite with Chert inclusions

Metamorphosed Quartz-rich Rock (SiO2)

Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

André Landed Here Rock (Glacial Erratic)

Granodiorite / Diorite (compositional estimate)

Quartzite

Quartzite (Primary mineral: Quartz, SiO2)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Blue Quartzite (Dyed)

Silicon Dioxide (SiO2) with inclusions

Green Quartzite

Quartzite (SiO2)

Quartzite Pebble

Quartzite (primarily SiO2)

Garnet Schist

Garnetiferous Micaceous Schist

Quartzite

Quartzite (SiO2)

Beach Quartzite Pebble

Quartzite (primarily SiO2)

Schist

Crystalline Schist (often containing Muscovite, Biotte, or Quartz)

Tiger's Eye

Pseudomorph of Crocidolite (SiO2 with iron oxides)

Banded Gneiss

Gneiss (typically quartz, feldspar, mica, amphibole composition)

Black Marble

Recrystallized Carbonate Rock (CaCO3)

Quartzite Pebble

Quartzite (predominantly Silicon Dioxide - SiO2)

Anthracite Coal

Anthracite

Quartzite

Quartzite (primarily SiO2)

Quartzite Cobble / Quartzite Pebble

Quartzite (SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions (Quartzite)

Ruby in Fuchsite (often sold as Ruby in Zoisite)

Corundum (Al2O3) in Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Dragon Blood Jasper (Epidote with Piedmontite or Quartz)

Epidote-rich Quartzite / SiO2 with (Ca2(Al2,Fe)(Si2O7)(SiO4)O(OH))

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Green Aventurine

Quartz (SiO2) containing Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)3Si3O10(OH)2)

Ruby in Zoisite (Anyolite)

Anyolite (Combination of Corundum and Zoisite)

Pyrite

Iron Disulfide (FeS2)

Yellow Quartzite

Quartzite (SiO2 with iron oxide inclusions)

Quartzite

Quartzite (SiO2)

Quartzite

Quartzite (SiO2)