Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Mica Schist with Garnet inclusions
Mica Schist (primarily Muscovite and Biotite - KAl2(AlSi3O10)(OH)2)
Orthoclase Feldspar
Potassium aluminum silicate (KAlSi3O8)
Titanium Coated Kyanite (Aura Kyanite)
Aluminosilicate (Al2SiO5) with a Titanium-Niobium vacuum-deposited coating
Riverstone Quartzite
Quartzite (primarily SiO2)
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
River Quartz Cobble
Silicon Dioxide (SiO2)
Blue Sapphire (likely costume glass imitation)
Corundum (Al2O3) with iron/titanium impurities
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Zinc Alloy (Silver-plated)
Zinc Alloy Casting (Zn-Al-Mg-Cu)
Pegmatite (likely Granitic Pegmatite)
Pegmatite (a coarse-grained igneous rock, often with granitic composition)
Coal (likely Bituminous or Lignite)
Organic Sedimentary Rock (Carbonaceous)
Chalk
Calcium Carbonate (CaCO3)
Bauxite
Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)
Fluorite Bracelet (light green beads) and possibly Lavender Jadeite (purple bead)
Fluorite: CaF₂ (Calcium Fluoride); Jadeite: NaAlSi₂O₆ (Sodium Aluminum Silicate)
Druzzy Quartz on Matrix
Silicon Dioxide (SiO2)
Serpentinite
Serpentinite (containing minerals of the Serpentine subgroup: Antigorite, Lizardite, and Chrysotile; formula (Mg,Fe)3Si2O5(OH)4)
Quartzite
Quartzite (primarily SiO2)
Quartzite Pebble
Quartzite (SiO2)
Banded Iron Formation (BIF) / Jasper
Banded Iron Formation (SiO2 with Fe2O3 and Fe3O4)
Anthracite Coal
Coal (predominantly carbon)
Synthetic Sapphire and Ion-X Glass
Single-crystal Alumina (Al2O3) and Ion-strengthened Aluminosilicate Glass
Quartzite
Quartzite (SiO2)
Basalt
Basalt
Quartzite (specifically an iron-stained or Carnelian-colored variety)
Silicon Dioxide (SiO2) with iron oxide inclusions
Quartz Geode (Water-worn)
Silicon Dioxide (SiO2)
Rose Quartz
Silicon Dioxide (SiO2) with trace impurities of Titanium, Manganese, or Iron
Quartz (Float/Abraded)
Quartz (SiO₂)
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Fluorite (likely)
Calcium Fluoride (CaF2)
Satin Spar (often marketed as Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Mica Schist
Foliated Metamorphic Rock (Schist)
Satin Spar (often marketed as Selenite)
Fibrous Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Fluorite
Fluorite (CaF₂)
Quartzite
Quartzite (SiO2)
Blue Calcite
Calcium Carbonate (CaCO3)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Black Tourmaline (Schorl)
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
White Marble
Recrystallized Calcite (CaCO3)
Marble
Recrystallized Calcite (CaCO3)
Gneiss (specifically Micaceous Gneiss)
Gneiss (High-grade Regional Metamorphic Rock)
Basalt
Basalt (composition of Plagioclase feldspar and Pyroxene)