Amethyst
Silicon dioxide with iron impurities (SiO2)
mineral
Category
Mineral Like Biological Tissue
Browse mineral like biological tissue specimens identified by the Rock Identifier community.
Aventurine and Amazonite
Silicon Dioxide (SiO2) with inclusions and Microcline (KAlSi3O8)
Mineral
Granite
Intrusive Phaneritic Felsic Igneous Rock
igneous
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Pink Granite
Felsic intrusive igneous rock (composition: SiO2 and Al2O3)
igneous
Ocean Jasper
Orbicular Jasper (Silicon Dioxide with impurities like Hematite and Chlorite, SiO2)
sedimentary
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
igneous
Metal Alloy (Jewelry)
Not a naturally occurring rock or mineral; likely a metal alloy for jewelry. Possible compositions include sterling silver (92.5% silver, 7.5% copper), or other silver/gold alloys.
Man-made Material (jewelry, metal alloy)
Azurite with Malachite
Azurite: Cu3(CO3)2(OH)2 / Malachite: Cu2CO3(OH)2
mineral
Gneiss
Gneiss
metamorphic
Schist
Schist (primarily mica-schist)
metamorphic
Rhodonite
Rhodonite (Mn, Fe, Mg, Ca)SiO3
mineral
Gneiss (specifically a Granitic Gneiss specimen)
Gneiss (high-grade metamorphic rock primarily composed of Quartz, Feldspar, and Biotite/Amphibole)
metamorphic
Howlite
Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Quartzite River Rock with Dendrites
Metamorphosed Quartz-rich Sandstone with Manganese Oxide (MnO2) inclusions
metamorphic
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Basalt
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
igneous
Agate
Agate (Microcrystalline Quartz, SiO2)
mineral
Shungite
Shungite (carbon-rich Precambrian mineraloid)
mineral
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Sandstone with Concretions / Liesegang Rings
Arenite with iron oxide banding
sedimentary
Quartz (Milky/Crystalline variety)
Silicon Dioxide (SiO2)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Volcanic Rock)
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Gneiss
Gneiss
metamorphic
Sunstone
Oligoclase (a plagioclase feldspar variant), (Na,Ca)(Al,Si)4O8
mineral
Chert (specifically Flint or Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Beryl (likely Emerald or Aquamarine in matrix)
Beryllium aluminum silicate (Be3Al2Si6O18)
mineral
Larimar
Pectolite (NaCa2Si3O8(OH))
mineral
Tufa
Calcareous Tufa (Calcium Carbonate, CaCO3)
sedimentary
Amber
Succinite (Resin C10H16O)
mineral
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
metamorphic
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Blue Sapphire
Corundum (Al2O3)
mineral
Pink Satin Spar (Satin Spar Selenite Dyed)
Gypsum (CaSO4·2H2O)
mineral
Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
mineral
Mica Schist with Quartz
Mica-Quartz Schist (Muscovite subclass)
metamorphic
Rough Garnet (likely Almandine or Pyrope)
Garnet group; Almandine Fe3Al2(SiO4)3 or Pyrope Mg3Al2(SiO4)3
mineral