Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Category
Browse mineral like byproduct (often mistaken for igneous rock or meteorite) specimens identified by the Rock Identifier community.
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Pyrite Nodules / Weathered Pyrite
Iron Sulfide (FeS2)
Granite (River Pebble)
Phaneritic intrusive igneous rock (Felsic)
Sandstone
Arenite
Vesicular Rhyolite
Extrusive igneous rock (high-silica rhyolite)
Quartz Geode Fragment
Silicon dioxide (SiO2) within a nodule
Banded Quartz
Silicon Dioxide (SiO2)
Sandstone
Arenite (predominantly Quartz Sandstone)
Granitic Gneiss
Gneiss (Metamorphic Rock)
Obsidian
Obsidian (volcanic glass; primarily SiO2)
Red Sandstone
Arenite (SiO2 with Fe2O3)
Quartz Pebble
Silicon Dioxide (SiO2)
Schist
Mica Schist
Greenstone / Greenschist
Greenschist (containing Chlorite, Epidote, Actinolite)
Porphyritic Basalt or Porphyritic Andesite
Porphyritic volcanic rock
Chert with Quartz/Calcite Vein
Microcrystalline Silica (SiO2)
Pumice
Felsic/intermediate vesicular extrusive rock
Sandstone Pebble
Arenite (primarily SiO2)
Sandstone (Tafoni Weathered)
Arenite (part of the Sandstone family)
Sandstone
Arenite (primarily SiO2)
Pumice
Pumice (a highly vesicular volcanic glass)
Milky Quartz
Silicon Dioxide (SiO2)
Red Sandstone
Arenite (primarily Quartz SiO₂ with Hematite Fe₂O₃ staining)
Milky Quartz
Silicon Dioxide (SiO2)
Turquoise in Matrix
CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)
Quartz pebble
Silicon dioxide (SiO2)
Sandstone / Limestone
Sedimentary Rock (Quartz Sandstone or Calcareous Grainstone)
Granite
Felsic Plutonic Rock
Corundum (Pink Sapphire / Ruby)
Al2O3 (Aluminum Oxide)
Quartz with Mica and Feldspar
Granitic Pegmatite Fragment (SiO2 + KAlSi3O8 + KAl2(AlSi3O10)(OH)2)
Picture Jasper
SiO2, Microcrystalline Quartz
Pink Granite
Phaneritic intrusive igneous rock (Felsic)
Fluorite
Fluorite (Calcium Fluoride, CaF2)
Brown Sandstone
Arenite (primarily Quartz and Feldspar, with Iron Oxide cement)
Sapphire
Corundum (Al₂O₃) with trace elements causing color variations.
Sandstone
Arenite (SiO2 principal composition)
Labradorite (likely)
(Ca,Na)(Al,Si)4O8
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Druzy Quartz
Crystalline Silicon Dioxide (SiO2)
Granite / Quartz with Mica inclusion
Granite (Plutonic Igneous Rock)
Blue Topaz (facetted in jewelry)
Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)
Hematite
Iron(III) oxide (Fe2O3)