Chert
Microcrystalline Quartz (SiO2)
Category
Browse mineral based human made alloy specimens identified by the Rock Identifier community.
Chert
Microcrystalline Quartz (SiO2)
Granite
Granite (Felsic Intrusive)
Pink granite
Coarse-grained felsic intrusive rock, chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende
Sandstone (Water-worn Cobble)
Arenite (SiO2 with CaCO3 or Fe2O3 cement)
Chert (or Flint)
Chert (a cryptocrystalline variety of quartz, SiO2)
Red jasper / red chert
Microcrystalline quartz (chalcedony), SiO₂, colored chiefly by iron oxides
Tumbled quartz-rich stone, possibly granite or sandstone
Uncertain from image; likely quartz (SiO₂) with iron-oxide and feldspar impurities
Chert (Cream Variety)
Microcrystalline silica (SiO2)
Sandstone
Arenite (primarily SiO2 with trace Fe2O3)
Milky Quartz with Chlorite/Mica inclusions
Silicon Dioxide (SiO2) with inclusions
Tumbled quartz-rich chalcedony (likely carnelian or orange jasper)
Microcrystalline quartz, SiO₂, colored mainly by iron oxides
Ferrous Slag
Iron/Steel Slag (Complex Calcium-Alumino-Silicates)
Stibnite (antimonite)
Stibnite, Sb₂S₃
Sandstone with Secondary Mineral Encrustation
Arenite with Silica/Calcite deposits (SiO2 or CaCO3)
Bumblebee Jasper
Calcite with Arsenic and Sulfur inclusions
Milky Quartz
Silicon dioxide (SiO2)
Fossilized Crinoid Stem Cross-Section
Crinoidea
Sandstone
Arenite (Sedimentary rock composed of sand-sized grains)
Hag Stone
Porous sedimentary rock (typically Flint, Chert, or Sandstone) with naturally occurring holes
Greenstone (Greenschist facies)
Greenschist (composed primarily of Chlorite, Actinolite, and Epidote)
Pebble
Lithified rock fragment / Sedimentary clast
Mixed Gemstone Beaded Jewelry
Various minerals (e.g., Quartz varieties like Rose Quartz, Amethyst; Peridot; Garnet; etc.)
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Chert / Flint
Microcrystalline Quartz (SiO2)
Granite (specifically Pink Granite)
Phaneritic Plutonic Rock (High Potassium Feldspar Granite)
Limonite (Iron Stone)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
N/A (This is a digital image of a bar graph)
Digital Data Visualization (Bar Chart)
Chert (Flint)
Chert (Microcrystalline or cryptocrystalline Quartz - SiO2)
Chert (specifically Zebra Chert/Flint)
Silicon Dioxide (SiO2)
Breccia
Breccia - Clastic sedimentary rock
Blue Topaz (specifically London Blue shade)
Topaz - Al2SiO4(F,OH)2
Silver (Morgan Dollar)
Native Silver (Ag) - 90% Silver, 10% Copper alloy
Sandstone (Ferruginous)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)
Green Aventurine
SiO2 (Silicon Dioxide with inclusions of Fuchsite)
Chert (variations include Chalcedony and Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Coquina
Biogenic Limestone (CaCO3)
Concrete with Aggregate
Composite construction material; primary matrix is Calcium Silicate Hydrate (C-S-H)
Copper-bearing rock, likely native copper in matrix
Native copper (Cu), possibly with cuprite/iron-rich matrix
Aquamarine
Beryl (Be₃Al₂Si‑₆O₁₈)
Aquamarine
Beryl (Be₃Al₂Si₆O₁₈)
Aura Quartz
Silicon Dioxide (SiO2) with metallic vapor coating
Siltstone with Fossil Cast
Sedimentary Rock (Siltstone / Fine-grained Sandstone)