Septarian Nodule
Septarian Concretion (CaCO3 with Siderite/Limonite streaks)
Category
Browse sedimentary rock (technically chert, a microcrystalline quartz) specimens identified by the Rock Identifier community.
Septarian Nodule
Septarian Concretion (CaCO3 with Siderite/Limonite streaks)
Chert (Tan/Grey variety)
Silicon Dioxide (SiO2)
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
Mookaite Jasper
Silicon Dioxide (SiO2) - variety of Chert/Jasper
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and clay impurities
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Agate
Silicon Dioxide (SiO2) - Chalcedony variety
Jasper
Jasper (SiO2 plus impurities)
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in Geode form
Granite Sand (Decomposed Granite)
Grus / Quartz-Feldspar Detritus
Quartz
Quartz (SiO₂)
Red Jasper (Chert)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Red Sandstone
Arenite (Ferruginous Sandstone)
Quartz
Quartz (SiO₂)
White Chalcedony (Agate)
Silicon Dioxide (SiO2)
Chert (Jasper-bearing)
Microcrystalline silica (SiO2) with iron oxide inclusions
Gneiss
Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)
Sandstone (Quartzose Sandstone Pebble)
Arenite (primarily SiO2)
Chalcedony (specifically Blue Chalcedony or Common Opal variety)
Silicon Dioxide (SiO₂)
Quartz Geode in Sedimentary Matrix
Silicon Dioxide (SiO2) within a limestone/dolostone host
Dalmatian Jasper (Dalmatian Stone)
Peralkaline rhyolite
Geode (unopened)
Calcedony-lined Geode (SiO2)
Druzy Quartz
Silicon Dioxide (SiO2)
Milky Quartz with Chlorite/Mica inclusions
Silicon Dioxide (SiO2) with inclusions
Quartz Geode
Silicon Dioxide (SiO2)
Sandstone (Greywacke/Siltstone variant)
Clastic Sedimentary Rock (composed primarily of Quartz SiO2 and Feldspar)
Limestone
Calcium Carbonate (CaCO3)
Basalt with Quartz Veins
Vesicular or aphanitic Basalt with SiO2 (Quartz) intrusions
Gneiss
Gneiss
Jasper
Silicon dioxide (SiO2) with iron impurities
Sandstone Concretion
Clastic Sedimentary Rock (primarily SiO2 with mineral cement)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Conglomerate
Conglomerate (SiO2 dominant in clasts)
Riverstone Quartzite
Quartzite (primarily SiO2)
Ironstone Concretion / Goethite Nodules
Ironstone (composed primarily of Goethite FeO(OH) and Limonite)
Ferruginous Sandstone
Sandstone with Iron Oxide (Limonite/Goethite)
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Jasper (Green Jasper / Chert)
Silicon Dioxide (SiO2) with iron/clay inclusions
Chert (Brown Variety)
Silicon dioxide (SiO2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide cement)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)