Ferruginous Sandstone (Ironstone Nodules)
Ferruginous Quartz-Arenite (with Goethite/Hematite cement)
sedimentary
Category
Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)
Browse sedimentary rock (technically a microcrystalline quartz mineral aggregate) specimens identified by the Rock Identifier community.
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Rose Quartz
Silicon Dioxide (SiO2) with trace titanium, iron, or manganese
mineral
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Gold Nugget
Native Gold (Au)
mineral
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
River Rocks (Black)
Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts
Sedimentary
Petrified Wood
Silicified wood (principally SiO2)
sedimentary
Glauconitic Sandstone
Glauconitic Quartz-Wacke / Sandstone (Fe(II),Fe(III),Al,Mg)2-3(Si,Al)4O10(OH)2
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
River Stone (Basalt Porphyry)
Porphyritic Basalt
igneous
Bull Quartz (Milky Quartz)
Quartz (Silicon Dioxide - SiO2)
mineral
Fossiliferous Limestone
Calcareous biomicrite / Bioclastic limestone
sedimentary
Riverstone Quartzite / Chalcedony Nugget
Silicon Dioxide (SiO2)
metamorphic
Sandstone (likely Quartzose Sandstone pebble)
Arenite (primarily SiO2)
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartzite (Iron-stained)
Quartzite (SiO2)
metamorphic
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (often called Flint)
Chert (Microcrystalline Silicon Dioxide, SiO2)
sedimentary
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
metamorphic
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Granite Cobble
Granite (Felsic Plutonic Rock)
igneous
Jasper (specifically Brecciated or Agated Jasper)
Silicon Dioxide (SiO2) - Chalcedony with impurities
Mineral / Sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
River Stone (likely Quartzite or Chert)
Recrystallized Silicon Dioxide (SiO2)
metamorphic
River Cobble (Conglomerate context)
Unconsolidated Fluvial Alluvium (comprised of various lithologies like Quartzite, Granite, or Basalt)
sedimentary
Greenstone / Chert
Cryptocrystalline Quartz (SiO2) or Altered Basalt
sedimentary or metamorphic
Quartz with Iron Staining
Silicon Dioxide (SiO2) with FeOx inclusions
mineral
Mica Schist with Iron Staining
Muscovite/Biotite Schist
metamorphic
Ironstone with Pyrite
Ferruginous Sandstone (Fe2O3) with minor Sulfide minerals (FeS2)
sedimentary
Basalt (River Rock/Cobble)
Basalt (no specific mineral formula as it's a rock)
Igneous
Biotite Mica
Biotite, K(Mg,Fe)3AlSi3O10(F,OH)2
mineral
Quartz / Iron-Stained Quartz
Silicon Dioxide (SiO2) with iron oxide inclusions/staining
mineral
Bog Iron / Limonite Concretion
Goethite/Limonite mixture (FeO(OH)·nH2O)
sedimentary
Porphyritic Basalt with Quartz Inclusions
Aphanitic Porphyritic Basalt
Igneous
Quartzite (Iron-stained)
Quartzite (SiO2)
metamorphic
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Granite (Weathered/Oxidized)
Phaneritic Felsic Igneous Rock (composed of Quartz, Orthoclase Feldspar, and Mica)
igneous
Chert (Yellow Jasper/Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary