Biotite Mica
K(Mg,Fe)3AlSi3O10(OH)2
Mineral in a matrix (likely quartz or feldspar)
Category
Anthropogenic Specimen (Man Made Material)
Browse anthropogenic specimen (man made material) specimens identified by the Rock Identifier community.
Banded Iron Formation (BIF)
Banded Iron Formation
Sedimentary Rock
Moqui Marble (Shaman Stone)
Ironstone Concretion (Fe2O3 - Hematite/Goethite shell with Sandstone core)
sedimentary
Quartz
Quartz (SiO₂)
Mineral
Pearl
Calcium Carbonate (mostly Aragonite), CaCO3 (with conchiolin)
mineral
Red Coral
Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.
Organic Gemstone (not a rock or mineral in the traditional sense, but bio-mineralized material)
Fuchsite
K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)
mineral
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Sand Dollar Fossil (Echinoidea)
Class Echinoidea (likely order Clypeasteroida), CaCO3 (Calcite)
sedimentary
Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
sedimentary
Granite
Granite (Mainly Quartz SiO2, K-Feldspar KAlSi3O8, and Plagioclase)
igneous
Quartz with Mica (Micaceous Quartz)
Silicon Dioxide (SiO2) with Phyllosilicates
igneous/metamorphic
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Quartzite (Iron-stained)
Quartzite (SiO2 with iron oxides)
metamorphic
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
mineral
Chalk
Micrite (primarily Calcium Carbonate, CaCO3)
sedimentary
Sandstone (Weathered Cobble)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Pearl
Aragonite (CaCO3) with Conchiolin
mineral
Goethite
Goethite (α-FeO(OH))
Mineral
Obsidian
Obsidian (volcanic glass)
igneous
Limestone
Calcium Carbonate (CaCO3)
sedimentary
White Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Serpentinite
Serpentinite (composed primarily of serpentine group minerals like lizardite, antigorite, and chrysotile)
metamorphic
Milky Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Moqui Marble (Shaman Stone)
Iron Oxide Concretion (composed primarily of Quartz sand with Hematite/Goethite shell)
sedimentary
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
mineral
Quartzite (River Stone)
Quartzite (SiO2)
metamorphic
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz (White or Milky Quartz Pebble)
Quartz (Silicon Dioxide, SiO2)
mineral
Limonitic Sandstone with Inclusion
Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Rose Quartz
Rose Quartz (SiO2)
Mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Chalcedony (Common Opal/Chert variety)
Silicon Dioxide (SiO2)
mineral
Banded Iron Formation
Banded Iron Formation (BIF)
sedimentary
Cobaltoan Calcite / Pink Dolomite (Possible)
Cobaltoan Calcite: (Ca,Co)CO3; Pink Dolomite (or Thulite): CaMg(CO3)2 or Mn-Dolomite / (Thulite: Mn2+3Al2(Si2O7)(SiO4)O(OH))
Mineral / Rock (depending on purity)
Granite
Granite (a common term for a felsic intrusive igneous rock)
igneous
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Halite (Rock Salt)
Halite; NaCl (Sodium Chloride)
Mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
mineral
Amethyst (variety of Quartz)
SiO2 (Silicon Dioxide) with trace iron impurities
Mineral