Slate
Foliated Metamorphic Rock (primarily composed of quartz, illite, chlorite, and micas)
Category
Browse synthetic or natural fiber specimens identified by the Rock Identifier community.
Slate
Foliated Metamorphic Rock (primarily composed of quartz, illite, chlorite, and micas)
Red Granite
Phaneritic Plutonic Felsic Rock (rich in Potassium Feldspar)
Magnetite
Magnetite (Fe3O4)
Diamond
Diamond (carbon allotrope), C (chemical formula)
Diamond (Rough)
Diamond (C)
Pebble (likely Quartzite or Chert)
Clastic Sediment, potentially composed of SiO₂ (Quartz)
Turquoise
Hydrated phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O
Ironstone Concretion / Limonite Node
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O) with Goethite/Hematite
Obsidian
Obsidian (volcanic glass), predominantly amorphous SiO₂
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Opalite (Man-made Glass)
Fused glass (typically made of dolomite and metal opacifiers)
Smoky Quartz
Smoky Quartz (Silicon Dioxide - SiO2)
Turquoise (Dyed Howlite or Magnesite imitation)
Hydrated phosphate of copper and aluminum / CuAl6(PO4)4(OH)8·4H2O
Diamond
Carbon (C)
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
Asphalt (Bituminous Concrete)
Asphaltum / Bitumen-Aggregate Matrix
Granite
Phaneritic Felsic Igneous Rock
White Agate (Tumbled)
Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony
Rainbow Fluorite
Fluorite (Calcium Fluoride, CaF2)
Pearl
Organic Mineral (CaCO3 with conchiolin)
Alexandrite
Chrysoberyl (BeAl2O4 with Chromium traces)
Pearl
Aragonite and Calcite (CaCO3) with Conchiolin
Sunstone
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
Turquoise (Tumbled/Polished)
Hydrated phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O
Smoky Quartz in Matrix (Pegmatite)
Silicon Dioxide (SiO2) with Potassium Feldspar and Biotite mica
Agate (Dyed High-Grade Polished Slice)
Silicon dioxide (SiO2), Chalcedony crystal variety
Ruby
Corundum (Aluminum Oxide with Chromium traces), Al2O3:Cr
Quartzite
Quartzite (SiO2)
Hand-Drawn Trading Card (Amateur Artwork)
Cellulose-based substrate with wax/graphite/ink deposit (n/a for minerals)
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Turquoise and Red Coral
CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Corallium rubrum (Red Coral)
Gold Nugget (Placer Gold)
Native Gold (Au)
Onyx (Black Onyx)
Onyx (Silicon Dioxide, SiO2)
Pearl
Calcium Carbonate (primarily Aragonite and Calcite), CaCO3
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Chert (Quartz Pebble)
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Amethyst (vibrant lilac/purple variety)
Silicon Dioxide (SiO2) with iron impurities
Granite
Intrusive Felsic Igneous Rock
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
Pearl (as a Biogenic Mineral)
Calcium Carbonate (mostly Aragonite) with Conchiolin; CaCO3