Angelite
Anhydrite (CaSO4)
mineral
Category
Mineralogical Specimen
Browse mineralogical specimen specimens identified by the Rock Identifier community.
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Petrified Wood
Silicified Wood (SiO2)
fossil
Gold Nugget (Placer Gold)
Native Gold (Au)
mineral
Iron-Stained Quartz
Silicon Dioxide with Iron Oxide (SiO2)
mineral
Common Opal (Potch)
Hydrated Silica (SiO2·nH2O)
mineral
Banded Siltstone
Siltstone (primarily composed of silt-sized grains)
sedimentary
Quartz with Arsenopyrite
Silicon Dioxide (SiO2) with Iron Arsenic Sulfide (FeAsS)
mineral
Jasper with Quartz Veining
Silicon Dioxide (SiO2) with iron oxide impurities
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Pink Quartz (Rose Quartz)
Silicon Dioxide (SiO2)
mineral
Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Dark Igneous Rock (Likely Basalt or Diabase)
Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.
Igneous
Labradorite
Plagioclase Feldspar ((Ca, Na)(Al, Si)4O8)
mineral
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Conical fossil shell or shell fragment
Likely a gastropod shell fragment; exact taxon indeterminate from the image
fossil
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
mineral
Polished red jasper pebble
Jasper, microcrystalline quartz (SiO₂) colored mainly by hematite/goethite
metamorphic
Common Opal with Host Rock
Opal (Hydrated silica, SiO2·nH2O)
mineral
Yellow Chalcedony (Tumbled/Cabochon)
Silicon dioxide (SiO2)
mineral
Bumblebee Jasper
Calcite-Auripigment-Pyrite-Realgar assemblage (Carbonate/Sulphide mixture)
mineral
Tiny amber-colored crystal fragment
Indeterminate; possibly quartz, feldspar, mica, or a sulfide mineral
mineral
Uncertain rounded gray stone
Possibly granite, gneiss, or a glacially transported granitoid
igneous
Polished/tumbled septarian nodule (likely)
Calcite–aragonite–barite septarian concretion; composition varies, commonly calcite (CaCO₃) with clay/mudstone and iron oxides
sedimentary
Amethyst
Quartz (Silicon Dioxide, SiO2)
gemstone
Vein-filled Porphyry or Brecciated Jasper Pebble
Brecciated volcanic rock with quartz/calcite veins
igneous
Basalt with Chert or Jasper Inclusion
Igneous basalt / sedimentary chert nodule
igneous
Jasper and Basalt (Lake Superior Agate or Jasper Pebble)
Silicified rock / Cryptocrystalline quartz (SiO2) with basalt matrix
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Lepidolite
K(Li,Al)3(Al,Si,3O10)(F,OH)2
mineral
Graphic Granite
Graphic Granite (Pegmatitic Alkaline Granite)
igneous
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Fire Quartz (Hematoid Quartz)
Silicon Dioxide with Hematite Inclusions (SiO2)
gemstone
Jasper
Silicon Dioxide (SiO2) microcrystalline quartz variety
sedimentary
Red Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Green Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Fossilized Bone
Permineralized Bone (Vertebrate Fossil)
fossil
Amethyst Geode
Quartz (SiO2)
mineral
Green Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Imperial Jasper
Microcrystalline Quartz (Chalcedony), SiO2
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Fossilized Coral (Petoskey Stone or similar Rugose Coral)
Hexagonaria percarinata (or similar Rugose/Tabulate coral)
fossil