Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Category
Browse metamorphic or sedimentary depending on local grade specimens identified by the Rock Identifier community.
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Red Jasper
Jasper (Silicon Dioxide with iron oxide inclusions), SiO2
Baroque Pearl (and potentially a small Sapphire/Blue Topaz)
Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.
Quartzite
Quartzite (SiO2)
Marble
Recrystallized Carbonate Rock (CaCO3)
Chert (Flint)
Chert (predominantly SiO₂ - silicon dioxide)
Calcite
Calcite (CaCO3)
Quartz (in a rock matrix)
Quartz (SiO2)
Quartzite (River Cobble)
Quartzite (primarily SiO2)
Green Aventurine
Silicon Dioxide with Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
Magnetite
Magnetite (Fe3O4)
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Limonite after Pyrite (Prophecy Stone or Ironstone Concretion)
Goethite/Limonite pseudomorph after Pyrite/Marcasite (FeO(OH)·nH2O)
Magnetite (Lodestone variety)
Magnetite (Iron(II,III) oxide, Fe3O4)
Clear Quartz
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Magnetite / Ironstone
Magnetite (Fe3O4)
Milky Quartz
Silicon Dioxide (SiO2)
Pyrite on Quartz
Iron Sulfide (FeS2) on Silicon Dioxide (SiO2)
Pyrite in Matrix (Quartz/Schist)
Iron Sulfide (FeS2)
Dyed Agate
Silicon Dioxide with artificial pigment (SiO2)
Quartz Veined Rock (Likely Graywacke or Quartzite)
Silicon Dioxide (SiO2) veins in Metasedimentary matrix
Thunderegg (Agate-filled Geode Node)
Silicon dioxide (SiO2) with various inclusions
Biotite (Mica)
Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)
Shale
Shale (fine-grained clastic sedimentary rock)
River Rocks (Black)
Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts
Druzy Quartz on Milky Quartz
Silicon Dioxide (SiO2)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Quartzite
Quartzite (primarily SiO2)
Quartzite (Rounded Pebble)
Quartzite (predominantly SiO2)
Yellow Quartzite Pebble
Quartzite (SiO2)
Chert (often called Flint for dark variants)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartzite
Quartzite (SiO2)
Zebra Marble
Metamorphosed Alabaster/Limestone (CaCO3)
Garnet Schist
Almandine-Garnet Mica Schist
Schist
Mica Schist (Variable chemistry, often rich in muscovite and biotite)
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Botryoidal Hematite (Kidney Ore)
Hematite (Fe2O3)
Blue Chalcedony
Microcrystalline Quartz (SiO2)
Gold
Aurum (Elemental Gold, Au)