Obsidian Arrowhead
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Category
Browse igneous or sedimentary (anthropogenic modification) specimens identified by the Rock Identifier community.
Obsidian Arrowhead
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Basalt Pebble
Basalt
Porphyritic Basalt (Chinese Writing Stone)
Porphyritic Basalt with Feldspar Phenocrysts
Basalt
Basalt (Mafic volcanic rock)
Vesicular Basalt (Iron-rich)
Scoriaceous Basalt / Oxidized Vesicular Basalt
Obsidian (Black)
Obsidian (approx. 70–75% SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
Granite
Phaneritic plutonic rock (approx. 20-60% quartz, 35-90% feldspar)
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions
Chondrite Meteorite Fragment
Ordinary Chondrite (L or H type)
Diorite
Diorite
Granite
Phaneritic Plutonic Rock (High Silica content)
Basalt Pebble
Basalt
Pink Granite
Phaneritic Acidic Plutonic Rock (primarily K-feldspar, quartz, and plagioclase)
Vesicular Basalt
Vesicular Basalt (Aphanitic Mafic Rock)
Basalt
Basalt
Basaltic Scoria
Scoria (Vesicular Basalt/Andesite)
Scoria (Basaltic)
Vesicular Basalt
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
Obsidian (Apache Tear)
Volcanic Glass (Amorphous Silicon Dioxide, SiO2)
Granite (with Beryl/Aquamarine)
Granite (Feldspar, Quartz, Mica, and Beryl Be3Al2Si6O18)
Basalt
Basalt (Mafic volcanic rock)
Pumice
Pumicite (Amorphous Volcanic Glass)
Pink Granite
Granite (Felsic Plutonic Rock)
Basalt
Basalt
Gossan (Iron Hat)
Limonitic Gossan (Fe-oxide/hydroxide complex)
Granite
Granite (composed primarily of Quartz SiO2, Orthoclase KAlSi3O8, and Plagioclase NaAlSi3O8 to CaAl2Si2O8)
Granite (Weathered)
Grano-diorite / Granite (SiO2 rich intrusive rock)
Andesite
Intermediate Volcanic Rock (Andesite)
Red Scoria (Lava Rock)
Vesicular Basalt / Scoria
Obsidian (Black Obsidian)
Obsidian (Volcanic Glass)
River Pebble (Gabbro or Dark Sandstone variety)
Mafic Intrusive Rock (Plagioclase Feldspar and Pyroxene)
Granite
Granite (Main minerals: Quartz SiO2, Feldspar KAlSi3O8, Mica)
Pegmatite
Granitic Pegmatite
Basalt with Porphyritic Texture
Porphyritic Basalt
Gabbro
Gabbro (composed mainly of calcium-rich plagioclase feldspar and pyroxene)
Porphyritic Rhyolite (Cookie Stone)
Porphyritic Rhyolite (SiO2, with phenocrysts)
Granite
Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)
Diorite
Diorite
Granite
Granite (Silicic Plutonic Rock)