Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
Category
Browse igneous rock specimens identified by the Rock Identifier community.
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
Quartz (Water-worn pebble)
Silicon Dioxide (SiO2)
Peridotite
Peridotite (varieties include Dunite, Lherzolite, Harzburgite)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Granodiorite
Granodiorite (Quartz + Plagioclase + Alkali Feldspar + Biotite/Hornblende)
River Cobble (Diorite or Meta-volcanic with Quartz Veining)
Diorite (with SiO2 quartz veins)
Pumice
Pumice (Volcanic silicate glass)
Vesicular Basalt (commonly mistaken for Slag)
Scoriaceous Basalt (composed primarily of Plagioclase Feldspar and Pyroxene)
Basalt with Phenocrysts (Porphyritic Basalt)
Porphyritic Basalt (primarily Plagioclase and Pyroxene)
Basalt
Basalt
Pumice
Pumice (Vesicular Rhyolite/Dacite)
Basalt with Olivine Phenocrysts
Porphyritic Basalt (Mineral formula of Olivine: (Mg,Fe)2SiO4)
Pumice
Pumice (a highly vesicular, silicic volcanic rock)
Snowflake Obsidian
Volcanic glass containing Cristobalite (SiO2)
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions)
Pink Granite
Granite (rich in Potassium Feldspar/Orthoclase)
Amygdaloidal Basalt
Amygdaloidal Basalt
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Granite
Phaneritic plutonic rock (primarily Quartz, Feldspar, and Mica)
Pumice
Pumice (Amorphous volcanic glass)
Basalt
Mafic Volcanic Basalt (Major minerals: Plagioclase feldspar, Pyroxene; Minor: Olivine, Magnetite)
Quartz (Druzy) in host rock
SiO₂ (Silicon Dioxide) as Quartz, with unspecified host rock components (likely silicates and iron oxides)
Quartz (Milk Quartz / Massive Quartz)
Silicon Dioxide (SiO2)
Smoky Quartz with Chert
Silicon Dioxide (SiO2)
Hypersthene (or Enstatite/Ferrosilite)
Orthopyroxene series (Mg,Fe)SiO3 - specifically, historically hypersthene (intermediate member) now referred to as Enstatite (Mg-rich) or Ferrosilite (Fe-rich)
Basalt
Basalt (Aphanitic Mafic Volcanic Rock)
Basalt
Basalt (Aphanitic Mafic Volcanic Rock)
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
Gneiss
Foliated Metamorphic Gneiss
Carnelian Agate
Carnelian (SiO2 with iron oxide impurities)
Conchoidal Basalt Pebble
Basalt with conchoidal fracturing
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Quartz (Iron-Stained or Milky)
Silicon Dioxide (SiO2)
Amethyst
SiO2 (Silicon Dioxide with Iron impurities and natural radiation influence)
Quartz (Milky or Common Quartz)
Silicon Dioxide (SiO2)
Smoky Quartz (Tumbled)
Silicon Dioxide (SiO2)
Bull Quartz
Quartz (Silicon Dioxide - SiO2)
Gneiss
Metamorphic Rock (Gneissic texture)
Gneiss (foliated metamorphic rock)
Gneiss
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Gneiss (Metamorphic Rock)
Gneiss