Porphyritic Basalt or Diabase with Plagioclase Phenocrysts
Porphyritic Basalt or Diabase; Mineral: Plagioclase Feldspar
Category
Browse mineral (impactite) specimens identified by the Rock Identifier community.
Porphyritic Basalt or Diabase with Plagioclase Phenocrysts
Porphyritic Basalt or Diabase; Mineral: Plagioclase Feldspar
Oolite or Oolitic Limestone
Oolitic Limestone (Principal mineral: Calcite, CaCO3)
Magnetite (Lodestone)
Magnetite (Fe3O4)
Snowflake Obsidian
Vitreous volcanic silicate (SiO2 with Cristobalite inclusions)
Milky Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Diamond
Diamond (pure Carbon, C)
Rough Diamond
Diamond (pure carbon, C)
Halite
Halite (Sodium Chloride, NaCl)
Diamond (in a gold ring setting)
Carbon (C)
Gneiss
Gneiss
Ironstone Concretion (Moqui Marble Type)
Goethite/Hematite-cemented Sandstone Concretion
Greenschist
Greenschist (Major minerals include Chlorite, Actinolite, and Epidote)
Quartzite (River Stone)
Quartzite (composed primarily of Silicon Dioxide, SiO2)
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Folded Schist / Gneiss (Metamorphic Rock)
Regional Metaphoric Folded Outcrop (predominantly Schist/Gneiss)
Rhodonite (in matrix)
Rhodonite (Mn,Fe,Mg,Ca)SiO3
Schist (Biotite/Mica Schist)
Medium-grade regional metamorphic rock (rich in Phyllosilicates)
Schist
Mica Schist
Shale
Fissile Mudstone (primarily composed of clay minerals and quartz)
Sandstone Concretion
Clastic Sedimentary Rock (primarily SiO2 with mineral cement)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Calcite
Calcite (Calcium Carbonate, CaCO3)
Fluorite
Calcium Fluoride (CaF2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Mica Schist
Mica Schist (predominantly Muscovite or Biotite sheet silicates)
Mixed collection of minerals and rocks (Jasper, Carnelian, Granite, and Quartz)
Silicon Dioxide (SiO2) with varying impurities for silicates and igneous aggregates
Basalt
Mafic volcanic rock (primarily Plagioclase and Pyroxene)
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals: (Mg,Fe)3Si2O5(OH)4)
Greenstone (Greenschist facies)
Greenschist (composed primarily of Chlorite, Actinolite, and Epidote)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Sandstone
Arenite (primarily SiO2 - Silicon Dioxide)
Jasper (Cream/Yellow variety)
Silicon Dioxide (SiO2) with impurities
Diorite
Intrusive Igneous Rock (Intermediate Composition)
Olivine in Basalt (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4 (Mineral) / Scoriaceous Basalt (Host Rock)
Diorite (River Cobble)
Intermediate plutonic igneous rock
Sandstone
Arenite (primarily composed of SiO2)
Arfvedsonite in Quartz (also labeled as Astrophyllite or Nuummite by collectors)
[Na][Na2][Mg4Fe2+](Si8O22)(OH)2 in SiO2
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
Granite
Phaneritic Felsic Igneous Rock
Sandstone (with cross-bedding)
Arenite (composed primarily of Quartz: SiO2)