Biotite Mica
K(Mg,Fe2+)3(Al,Fe3+)Si3O10(OH,F)2
Category
Browse mineral on igneous rock specimens identified by the Rock Identifier community.
Biotite Mica
K(Mg,Fe2+)3(Al,Fe3+)Si3O10(OH,F)2
Pink Granite
Phaneritic Felsic Igneous Rock (composed primarily of K-Feldspar, Quartz, and Mica)
Basalt
Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Gneiss
Gneiss
Rough Corundum (likely Sapphire/Zircon-bearing)
Aluminium Oxide (Al2O3)
Banded Gneiss
Gneiss (High-grade regional metamorphic rock)
Coarse Sand Grain / Lithic Fragment
Clastic Sediment (Lithic fragment or Quartz/Feldspar grain)
Granite
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
Basalt with Quartz/Plagioclase Inclusions
Mafic volcanic rock (Basaltic)
Granite
Granite (a plutonic igneous rock composed of quartz, feldspar, and mica)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide
Obsidian
Obsidian (Volcanic Glass)
Granite Pebble
Granite (a plutonic igneous rock composed primarily of quartz, feldspar, and mica/amphibole)
Milky Quartz (with Iron Oxide staining)
Silicon Dioxide (SiO2)
Granite (with Almandine Garnet inclusions)
Granite composed primarily of Quartz (SiO2), K-Feldspar (KAlSi3O8), and Almandine Garnet (Fe3Al2(SiO4)3)
Granite
Granite (Felsic intrusive igneous rock)
Pink Granite
Granite (Phaneritic felsic intrusive igneous rock)
Basalt
Mafic Igneous Rock
Basalt
Mafic Igneous Rock
Vesicular Basalt
Mafic Igneous Rock
Quartz
Silicon Dioxide (SiO2)
Granite
Phaneritic plutonic rock (SiO2 typically >69%)
Diorite
Diorite (Intermediate intrusive igneous rock)
Agate (Moss or Plume Agate variety)
Silicon Dioxide (SiO2)
Diorite
Diorite (Intermediate intrusive igneous rock)
Olivine-bearing Basalt / Scoria
Mafic Igneous Rock (primarily (Mg, Fe)2SiO4)
Basalt
Mafic Igneous Rock
Basalt
Mafic Igneous Rock
Basalt
Mafic Igneous Rock
Basalt River Stone
Basaltic Igneous Rock
Milky and Citrine-type Quartz
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Amygdaloidal Basalt
Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)
Quartz / Milky Quartz
Silicon Dioxide (SiO2)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Granite
Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)
Clear Quartz
Silicon Dioxide (SiO2)
Vesicular Basalt (Iron-Stained)
Mafic Volcanic Rock (Basalt)
Milky Quartz/Clear Quartz Cluster
Silicon Dioxide (SiO2)
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)