Basalt
Basalt
Category
Browse igneous (anthropogenic) specimens identified by the Rock Identifier community.
Basalt
Basalt
Granite
Phaneritic Igneous Rock (composed primarily of Quartz SiO2, Alkali Feldspar (K,Na)AlSi3O8, and Plagioclase Feldspar)
Porphyritic Andesite
Andesite (Porphyry)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2)
Vesicular Basalt with Amygdules
Amygdaloidal Basalt
Granite
Granite
Pink Granite
Granite (composed primarily of Quartz, K-Feldspar, and Plagioclase)
Granite
Granite (compositional mixture of Quartz, Feldspar, and Mica)
Scoria (Lava Rock)
Vesicular Basalt / Scoria
Pegmatite (with smoky quartz and tourmaline/biotite)
Pegmatitic Granite
Pink Granite
Phaneritic Quartz-Feldspar Granite
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
Basalt
Basalt (Mafic Extrusive)
Scoria
Vesicular Basalt / Scoria (Mafic volcanic rock)
Porphyritic Basalt (Chinese Writing Stone or Flower Stone)
Porphyritic Basalt / Porphyry
Basalt River Stone
Basalt
Obsidian
Volcanic Glass (SiO2 + minor impurities)
Scoria (Lava Rock)
Scoria (extrusive volcanic rock)
Obsidian
Volcanic Glass (SiO2)
Bumblebee Jasper
Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)
Granite
Granite (comprised primarily of Quartz (SiO2), Feldspar (KAlSi3O8), and Mica (KAl2(AlSi3O10)(OH)2))
Granite Cobble
Granite
Mahogany Obsidian
Volcanic glass (SiO2 with Hematite or Magnetite inclusions)
Basalt
Basalt
Granite
Granite (composed primarily of Quartz SiO2 and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8))
Diorite (Salt and Pepper Rock)
Phaneritic Plutonic Diorite (Plagioclase Feldspar + Amphibole/Biotite)
Basalt
Basalt (Mafic volcanic rock)
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Basalt
Mafic volcanic rock (Primary minerals: Plagioclase feldspar, Pyroxene)
Basalt with Quartz/Feldspar Vein
Amygdaloidal Basalt with Plutonic intrusion (SiO2/KAlSi3O8)
Diorite
Phaneritic Intermediate Plutonic Rock (Diorite)
Pink Granite (Gneissic transition)
Pink Biotite Granite
Granite
Granitoid (composition typically SiO2, Al2O3, K2O, Na2O)
Granite
Granite (Phaneritic intrusion / SiO2 + KAlSi3O8 + NaAlSi3O8)
K2 Jasper (K2 Granite)
Azurite-in-Granite
Thunderegg (Agetized Geode nodule)
Rhyolitic Agate Nodule (SiO2 filling volcanic cavities)
Basalt
Basalt (Mainly Plagioclase Feldspar and Pyroxene)
Porphyritic Basalt (Chinese Writing Stone/Flower Stone)
Porphyritic Basalt (primarily Plagioclase Feldspar in a Mafic groundmass)
Basalt
Basalt (Aphanitic-to-porphyritic mafic volcanic rock)
Vesicular Basalt with Quartz/Chalcedony
Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)
Porphyritic Andesite (often called Chinese Writing Stone)
Porphyritic Basaltic Andesite with Feldspar Phenocrysts