Basalt
Basalt (extrusive igneous rock)
Igneous
Category
Synthetic (Not A Rock Or Mineral)
Browse synthetic (not a rock or mineral) specimens identified by the Rock Identifier community.
Pyrite on Quartz matrix
Iron Disulfide (FeS2) on Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Agate
Silicon Dioxide (SiO2)
mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Sandstone (Ferruginous)
Arenite with Iron Oxide cement (SiO2 + Fe2O3)
sedimentary
Basalt with Quartz/Feldspar Inclusions
Amygdaloidal or Porphyritic Mafic Volcanic Rock with Siliceous Veining
igneous
Amygdaloidal Basalt with Agate/Chalcedony Infills
Amygdaloidal Basalt (Composition: SiO2 and (Mg,Fe)2SiO4 in matrix; SiO2 in amygdule)
igneous
Limestone Breccia
Sedimentary Breccia (Calcareous)
sedimentary
Goldstone (Red)
Aventurine Glass (Cupriferous glass)
Synthetic Glass (Man-made)
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily Quartz, SiO2)
sedimentary
Sandstone (likely Ferruginous)
Sandstone (SiO2 with iron oxides)
sedimentary
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
sedimentary
Turquoise
Turquoise (CuAl6(PO4)4(OH)8·4H2O)
mineral
Dalmatian Stone
Dalmatian Jasper (a misnomer for an Aplite with Arfvedsonite spots)
igneous
Sandstone (Ferruginous)
Arenite with Iron Oxides
sedimentary
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
mineral
Sandstone
Arenite (Siliclastic sedimentary rock), SiO2 + various minerals
sedimentary
Shale
Fissile Siliciclastic Sedimentary Rock
sedimentary
Sandstone
Sandstone (composed primarily of sand-sized minerals or rock grains)
sedimentary
Druzy Quartz Geode (Vug)
Silicon Dioxide (SiO2)
mineral
Quartz Pebble (Water-worn Quartzite)
Silicon Dioxide (SiO2)
metamorphic
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Lapis Lazuli
Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2
metamorphic
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
metamorphic
Quartz Vein in Host Rock (Gabbro or Basalt)
Silicon Dioxide (SiO2) with Mafic Silicates
metamorphic/igneous
Shale
Shale (Sedimentary rock composed of mud/clay minerals)
sedimentary
Quartz Geode
Quartz (Silicon Dioxide - SiO2) within a Chalcedony and Limonite shell
sedimentary
Dalmatian Stone
Peralkaline Feldsphathic Igneous Rock
igneous
Granitic Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Greywacke (River Pebble with Quartz Veins)
Greywacke (Indurated Sandstone); Veins: SiO2 (Quartz)
sedimentary
Greenstone (Epidote/Chlorite Rich Rock)
Metabasalt (often contains Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))
metamorphic
Limonite with Opal infusion
FeO(OH)·nH2O (Limonite) / SiO2·nH2O (Opal)
mineral
Sandstone with Quartz Veining
Clastic sedimentary rock (SiO2 dominated)
sedimentary
Sandstone Concretion
Sedimentary concretion
Sedimentary
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
sedimentary
Green Moonstone (Garnierite)
Nickel-bearing Magnesium Silicate (often a mix of Serpentine and Talc/Chlorite groups)
mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Quartz Vein in Host Rock (Pebble)
Quartz (SiO2) with sandstone or siltstone matrix
metamorphic/igneous transition
Granite
Phaneritic Felsic Igneous Rock (Main minerals: SiO2, KAlSi3O8, NaAlSi3O8)
igneous
Hypersthene
Hypersthene (formula: (Mg,Fe)SiO3)
mineral
Mica Schist
Mica Schist (primarily Muscovite or Biotite sheet silicates)
metamorphic