Ferruginous Sandstone
Arenite with Iron-oxide cement
Category
Browse metamorphic (likely gneiss or schist based on texture) specimens identified by the Rock Identifier community.
Ferruginous Sandstone
Arenite with Iron-oxide cement
Sunstone
Oligoclase (Plagioclase Feldspar subclass), (Ca,Na)(Al,Si)4O8
Tree Agate (Dendritic Agate)
Silicon Dioxide (SiO2) with Manganese/Iron inclusions
Granite Cobble
Granite (Phaneritic igneous rock composed of Quartz, Feldspar, and Mica)
Sandstone (Stream-rounded Cobble)
Arenite (composed primarily of SiO2, Silica)
Scoria (Lava Rock)
Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)
Quartz
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite (Fe-bearing Clastic Sedimentary Rock)
Sandstone (Weathered Coastal Boulder)
Arenite (composed primarily of SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (Yellow or Ochre Jasper variant)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Sandstone (Ferruginous)
Sandstone (primarily SiO2 with Iron Oxide cement)
Quartz Pebble
Silicon Dioxide (SiO2)
Amazonite
K(AlSi3O8), Microcline (potassium feldspar)
Sandstone
Arenite (SiO2 principal)
Yellow Quartz Pebble (Citrine or Iron-Stained Quartz)
Silicon Dioxide (SiO2)
K2 Jasper (Beads)
Granodiorite with Azurite and Malachite
Andesite River Stones
Andesite
Tektite (Indochinite)
Tektite (High-silica natural glass)
Dragon Blood Jasper
Epidote with Red Jasper inclusions (SiO2 and Ca2(Al,Fe)3(SiO4)3(OH))
Sandstone (Flagstone)
Arenite (composed primarily of SiO2)
Sandstone (with banding)
Arenite (primarily SiO2)
Marble (White)
Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)
Metal Alloy (Likely Pewter or Sterling Silver)
Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).
Sandstone with Ironstone Banding
Clastic Sandstone (composed of Quartz with Hematite/Limonite bonding)
Citrine Quartz
SiO2 (Silicon Dioxide with Iron impurities)
Pumice
Pumicite
Basalt with vesicles/amygdules
Basalt (containing volcanic glass and plagioclase)
Sandstone (likely Arkose or Quartz Sandstone)
Arenite (SiO2 principal component)
River Pebble (Gabbro or Dark Sandstone variety)
Mafic Intrusive Rock (Plagioclase Feldspar and Pyroxene)
Quartzite
Quartzite (primarily SiO2)
Massive Quartz with Host Rock
Silicon Dioxide (SiO2)
Amazonite
Amazonite (KAlSi3O8)
Jasper Quarzite (possibly Lake Superior Agate mix)
Silicon Dioxide with Iron Oxide inclusions (SiO2 + Fe2O3)
Sandstone (Quartzose Sandstone)
Arenite (SiO2 primarily)
Jasper with Quartz Druzy
Silicon Dioxide (SiO2)
Basalt (Weathered/Tumbled)
Extrusive Mafic Igneous Rock
Basalt with Scoria
Mafic Volcanic Rock (Basalt/Scoria)
Serpentinite
Serpentinite (composed mainly of Group: Serpentine; (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
Quartz (specifically Milky Quartz or Quartzite)
Silicon Dioxide (SiO2)
Chert (Chert Nodule with Cortex)
Microcrystalline Quartz (SiO2)