Ironstone Concretion (likely)
Goethite/Hematite/Limonite cemented sediment
Category
Browse mineral (specifically a variety of chalcedony, which is a microcrystalline quartz) specimens identified by the Rock Identifier community.
Ironstone Concretion (likely)
Goethite/Hematite/Limonite cemented sediment
Quartz
Silicon Dioxide (SiO2)
Pyrite in Quartz (Drill Core)
Silicon Dioxide (SiO2) with Iron Sulfide (FeS2) inclusions
Chert (Chalcedony / Gray Flint)
Silicon Dioxide (SiO2)
Botryoidal Agate
Chalcedony (Silicon Dioxide, SiO2)
Pink Quartzite
Quartzite (primarily SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Rose Quartz
Quartz (Silicon Dioxide, SiO2)
Chert (often called Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Sandstone Beach Pebble
Clastic Sedimentary Rock (primarily Quartz with Iron Oxide coating)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Grey Agate
Silicon Dioxide (SiO2) - variety: Agate/Chalcedony
Carnelian
Carnelian (a variety of Chalcedony); SiO2 (Silicon Dioxide)
Bloodstone (Heliotrope)
Silicon Dioxide (SiO2) - Variety of Chalcedony/Jasper
Blue Dyed Agate Geode Slice
Chalcedony (Silicon Dioxide, SiO2) with artificial cobalt/iron-based dye
Ferruginous Quartzite (Red Chert/Jasper-like)
Metamorphosed Quartzite with Hematite inclusions (SiO2 + Fe2O3)
Chert (with Quartz Druzy)
Microcrystalline Silica (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartzite
Quartzite (primarily SiO2)
Fire Agate
SiO2 (Silicon Dioxide with Iron Oxide inclusions)
Tiger's Eye (Brown/Gold variety)
Pseudomorph of Quartz after Crocidolite (SiO2 with FeOOH inclusions)
Petrified Wood (Agatized/Silicified Wood)
Silicified Wood (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Quartzite River Pebble
Quartzite (primarily SiO2)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxide
Sandstone Pebble with Iron Staining
Clastic Sedimentary Rock (primarily Quartz with Fe2O3 oxides)
Jasper
Silicon dioxide (SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Quartz
Silicon dioxide (SiO2)
Quartzite
Quartzite (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz Pebble
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz Pebble
Silicon Dioxide (SiO2)
Quartz (Milky variant)
Silicon Dioxide (SiO2)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz (Milky/Bull Quartz)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)