Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions
Category
Browse man made glass specimens identified by the Rock Identifier community.
Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions
Serpentine Schist with Quartz Vein
Serpentine Schist (a type of Metamorphic rock). The white band is likely Quartz (SiO2).
Granite
Granite (a felsic intrusive igneous rock)
Blue Chalcedony and Picture Jasper Beads
Blue Chalcedony (SiO2), Picture Jasper (SiO2)
Basalt (Lava Rock) and Dyed Glass/Quartz
Scoria (Vesicular Basalt)
Chalcedony (Banded/Mottled Variety)
Chalcedony (a cryptocrystalline variety of Quartz, SiO2)
Fluorite
Fluorite (Calcium Fluoride, CaF2)
Quartz Vein on Matrix
Silicon Dioxide (SiO2)
Flint
Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)
Snowflake Obsidian
Obsidian (volcanic glass) with Cristobalite inclusions
Quartz (chalcedony variety) or Limestone with Quartz Veins
SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)
Banded Iron Formation
Banded Iron Formation (BIF)
Granite
Plutonic felsic igneous rock
Chert (Black Chert/Flint)
Silicon Dioxide (SiO2)
Granite
Granite (Phaneritic Igneous Rock)
Granite Pebble
Igneous Intrusive Rock (Quartz-Feldspar-Mica Phenocrysts)
Olivine in Basalt matrix
Peridotite (Mg, Fe)2SiO4
Druzy Quartz
Quartz (Silicon Dioxide, SiO2)
Quartzite
Quartzite (primarily SiO2)
Lapis Lazuli
A metamorphic rock primarily composed of lazurite (Na,Ca)8[(S,SO4,Cl)2|(Al6Si6O24)], calcite (CaCO3), and pyrite (FeS2).
Granite
Felsic Plutonic Rock (primarily SiO2)
Granite
Phaneritic plutonic rock (Quartz + Feldspar + Mica)
Ferruginous Slag (Iron Smelting Byproduct)
Anthropogenic Vitreous Silicate (often containing Fayalite: Fe2SiO4)
Calcite
Calcite (CaCO3)
Sandstone (Ferruginous)
Arenite (with Iron Oxide)
Granite
Granite (Felsic Plutonic Rock)
Granite
Plutonic felsic igneous rock
Quartz (Yellow/Citrine variety)
Crystalline Silicon Dioxide (SiO2)
Olivine in Basalt
Peridotite / Forsterite ((Mg,Fe)2SiO4)
Diorite (possibly fine-grained variety or a related intermediate intrusive rock like a felsic gabbro or a dark granodiorite)
Diorite (Igneous rock, intrusive, intermediate composition)
Sandstone
Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)
Quartz Pebble (often referred to as 'Sea Glass' or 'River Stone' when worn smooth)
Silicon Dioxide (SiO2)
Limestone (specifically Travertine or Tufa)
Calcium Carbonate (CaCO3)
Diabase (also known as Dolerite)
Diabase / Dolerite
Sandstone (with potential mineral inclusions)
Clastic sedimentary rock (primarily Quartz, SiO2)
Granite
Course-grained intrusive igneous rock
Granite River Rock
Phaneritic Felsic Igneous Rock (Granite)
Strawberry Quartz
Quartz with Hematite inclusions (SiO2 + Fe2O3)
Sandstone
Arenite (SiO2 with various cementing agents)
Sandstone
Arenite (SiO2 based)
Olivine in Basalt matrix
Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)