Gray Basalt
Basalt (Mafic Extrusive Igneous Rock)
Category
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Gray Basalt
Basalt (Mafic Extrusive Igneous Rock)
Anthracite Coal with Sulfur staining
Anthracite (Carbon C with impurities)
Conglomerate
Conglomerate (Sedimentary Rock)
Magnetite (Iron Ore)
Magnetite (Fe3O4)
Peridotite (with Olivine)
Peridotite (rich in Olivine, (Mg,Fe)2SiO4)
Quartzite
Quartzite (SiO2)
Pink Quartzite
Quartzite (primarily SiO2)
Diorite river pebble
Diorite (intermediate plutonic rock)
Quartzite (River Pebble)
Metamorphosed Quartz Sandstone (SiO2)
Red Jasper
Silicon Dioxide with Iron Oxide (SiO2)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Aquamarine
Aquamarine (Beryl variety); Be3Al2Si6O18
Quartzite (or Quartz Rich Conglomerate)
Quartzite (SiO2 silicon dioxide)
Quartzite
Quartzite (consisting primarily of SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Charoite with Aegirine inclusions
(K,Sr)15-16(Ca,Na)32[Si6O11(O,OH)6]2[Si12O18(O,OH)12]2[Si17O25(O,OH)18]2(OH,F)4.0-3.0 * nH2O + NaFeSi2O6
Quartz (Gray or Smoky variety)
Silicon Dioxide (SiO2)
Sandstone
Arenite (primarily SiO2)
Ferruginous Quartz
Quartz (Silicon Dioxide) with Iron Inclusion (SiO2 + Fe2O3)
Chert (often called Flint when dark or found in chalk)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartzite Cobble
Quartzite (SiO2)
Sandstone with Quartz Vein
Arenite with Quartz (SiO2) Infilling
Shale with Limonite/Hematite Staining
Argillaceous sedimentary rock with Iron Oxides (FeO(OH)·nH2O / Fe2O3)
Sandstone (Weathered Pebble)
Arenite (primarily SiO2)
Quartzite
Quartzite (SiO2)
Wishing Stone (Basalt/Siltstone with Quartz/Calcite vein)
Carbonaceous Siltstone with Quartz (SiO2) or Calcite (CaCO3) vein
Botryoidal Hematite (Iron Ore)
Iron(III) oxide (Fe2O3)
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
Granite
Phaneritic Felsic Igneous Rock (composed主に of SiO2, Al2O3, K2O, Na2O)
Ferruginous Quartz
Silicon Dioxide with Iron Oxide inclusions (SiO2 + Fe2O3)
Quartzite
Metamorphosed Quartz Arenite (SiO2)
Chert (Arrowhead/Projectile Point)
Microcrystalline Quartz (SiO2)
Citrine Quartz
Silicon Dioxide (SiO2)
Ironstone Concretion (Moqui Marble type)
Ferruginous Concretion (Fe2O3 / FeO(OH))
Sandstone
Arenite (composed primarily of SiO2)
Quartz (with probable host rock)
Silicon Dioxide (SiO2)
Quartzite
Quartzite (SiO2)
Beach Quartzite Pebble
Quartzite (primarily SiO2)
Pink Quartzite
Quartzite (primarily SiO2)
Quartzite
Quartzite (SiO2)
Rose Quartz
Silicon Dioxide (SiO2)