Pumice
Pumicite (Amorphous volcanic glass)
Category
Browse igneous (anthropogenic) specimens identified by the Rock Identifier community.
Pumice
Pumicite (Amorphous volcanic glass)
Olivine (Peridotite)
Magnesium Iron Silicate - (Mg, Fe)2SiO4
Scoria (with likely iron oxidation)
Scoria (Basaltic Scoria)
Porphyry
Porphyritic Rock
Basalt River Cobble
Basalt (Composition primarily Plagioclase Feldspar and Pyroxene)
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Arfvedsonite with Garnet
Na3(Fe2+,Mg)4Fe3+Si8O22(OH)2
Granodiorite
Granodiorite (Intermediate to Felsic Intrusive Rock)
Amygdaloidal Basalt
Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)
Basalt
Basalt
Obsidian
Obsidian (Volcanic Glass, complex silicate)
Pumice
Pumice (a volcanic glass, primarily SiO2 with Al2O3)
Granite
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Quartz-veined Basalt
Amygdaloidal or Porphyritic Basalt with Silicon Dioxide (SiO2) vein
Obsidian
Volcanic glass
Granite
Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)
Granite
Granite (Mainly Quartz SiO2, K-Feldspar KAlSi3O8, and Plagioclase)
Pink Tourmaline (Rubellite) in Lepidolite
Elbaite (Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)4) in Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
Porphyry
Porphyritic Basalt/Andesite
Obsidian
Obsidian (Amorphous Volcanic Glass, SiO2)
Granite
Phaneritic intrusive igneous rock (composed mainly of Quartz SiO2, Feldspar KAlSi3O8, and Biotite/Mica)
Basalt
Basalt
Granite Cobble
Plutonic Granite
Pumice
Pumice (Amorphous volcanic glass)
Diorite (Salt and Pepper Rock)
Diorite
Basalt River Stone
Basalt (Aphanitic Mafic Volcanic Rock)
Feldspar Granodiorite
Granodiorite (Na,Ca)(Si,Al)4O8
Basalt
Basalt (High-iron/magnesium silicate rock)
Granite
Granite (Felsic Plutonic Rock)
Basalt
Basalt
Amygdaloidal Rhyolite (often called Lake Superior Agate relative)
Rhyolite with Calcite/Quartz amygdules (SiO2 and secondary minerals)
Pumice
Pumice (Highly vesicular volcanic glass)
Granite or Pegmatite with Mica
Granitoid
Diorite (Spotted or Dalmatian Stone pattern)
Diorite
Obsidian
Volcanic Glass (SiO2)
Basalt River Pebble
Basalt (Mafic Extrusive Volcanic Rock)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
Porphyritic Basalt (or Andesite) Pebble
Porphyritic Mafic Volcanic Rock
Basalt
Basalt (composition of Plagioclase feldspar and Pyroxene)
Scoria (with Iron Oxidation)
Vesicular Basalt / Scoria
Granite (specifically Red Granite)
Phaneritic Plutonic Rock (High in Alkali Feldspar and Quartz)