Clear Quartz
Silicon Dioxide (SiO2) / Rock Crystal
Category
Browse mineral in igneous rock specimens identified by the Rock Identifier community.
Clear Quartz
Silicon Dioxide (SiO2) / Rock Crystal
Green Calcite
Calcium Carbonate (CaCO3)
Basalt
Basalt (composition predominately Plagioclase feldspar and Pyroxene)
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
Basalt (Vesicular/Amygdaloidal)
Basalt
Granite
Granite (Felsic Plutonic Rock)
Granite
Granite (Felsic Plutonic Rock)
Vesicular Basalt
Basalt (Mafic volcanic rock)
Crushed Stone (Basalt/Gabbro)
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
Basalt (with possible quartz veinsing)
Basalt
Ruby in Zoisite
Anyolite (Calcium Aluminum Silicate with Aluminum Oxide impurities)
Milky Quartz
Silicon Dioxide (SiO2)
Granite
Granite (Felsic Plutonic Rock)
Granite
Granite (Felsic Plutonic Rock)
Thunderegg (Agetized Geode nodule)
Rhyolitic Agate Nodule (SiO2 filling volcanic cavities)
Vesicular Basalt with Quartz
Vesicular Basalt (SiO2 inclusions)
Greenstone Pebble
Metabasalt (often containing chlorite, actinolite, or epidote)
Quartz (likely Milky Quartz)
Quartz (SiO₂ - Silicon Dioxide)
Yellow Agate
Chalcedony (cryptocrystalline Quartz), SiO2
Yellow Quartz (Iron-Stained Quartz)
Silicon Dioxide (SiO2) with iron oxide inclusions
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Vesicular Basalt (Pumice-like)
Vesicular Basalt
Granodiorite
Granodiorite (containing Plagioclase, Quartz, and Biotite)
Milky Quartz
Silicon Dioxide (SiO2)
Pebble (Likely Basalt or Siltstone)
Clastic sedimentary rock or mafic volcanic rock
Milky Quartz (Water-worn Pebble)
Silicon Dioxide (SiO2)
Scoria (with Iron Oxidation)
Vesicular Basalt / Scoria
Vesicular Basalt (commonly mistaken for Slag)
Scoriaceous Basalt (composed primarily of Plagioclase Feldspar and Pyroxene)
Granodiorite Pebble
Granodiorite (Intermediate intrusive igneous rock)
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
Blue Sapphire
Corundum (Al2O3)
Basalt (Vesicular)
Vesicular Basalt
Basalt
Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Basalt
Extrusive mafic igneous rock; primarily (Ca,Na)(Mg,Fe,Al,Si)2O6 with (Ca,Na)(Al,Si)4O8
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Basalt
Extrusive mafic igneous rock
Basalt
Extrusive mafic igneous rock
Quartz
Quartz (SiO₂)
Granite
Felsic Plutonic Rock (primarily SiO2, Al2O3, K2O, Na2O)
Basalt with Weathering Crust
Extrusive mafic volcanic rock
Banded Gneiss
Foliated Gneiss