Geode (unopened) or Calcareous Nodule
Siliceous or Calcareous Concretion/Nodule
sedimentary
Category
Not A Rock (Man Made Origin)
Browse not a rock (man made origin) specimens identified by the Rock Identifier community.
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Basalt with Quartz/Feldspar Inclusions
Amygdaloidal or Porphyritic Mafic Volcanic Rock with Siliceous Veining
igneous
Sandstone Beach Pebble
Clastic Sandstone (SiO2 - Quartz-dominant)
sedimentary
Rough Tanzanite
Zoisite (Ca2Al3(SiO4)3(OH))
mineral
Chert (Flint)
Chert (SiO2)
sedimentary
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
mineral
Banded Chert or Agate
Silicon Dioxide (SiO2)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Diabase
Diabase (also known as Dolerite)
igneous
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (specifically Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Pink Opal
Amorphous Hydrous Silica (SiO2·nH2O)
mineral
Olivine/Peridot
Magnesium Iron Silicate (Mg,Fe)2SiO4
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic extrusive volcanic rock with secondary mineral infilling)
igneous
Banded Chert (Agate-like Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Amethyst (Rough)
Silicon Dioxide with iron impurities (SiO2)
mineral
Quartz Veined Siltstone or Graywacke
Clastic Sedimentary Rock with Quartz (SiO2) veining
sedimentary
Amygdaloidal Basalt with Agate/Chalcedony Infills
Amygdaloidal Basalt (Composition: SiO2 and (Mg,Fe)2SiO4 in matrix; SiO2 in amygdule)
igneous
Limestone Breccia
Sedimentary Breccia (Calcareous)
sedimentary
Chert / Jasper / Agate (Chalcedony Group)
Microcrystalline Quartz (SiO2)
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt containing Zeolite or Quartz (SiO2/Silicates)
igneous
Yellow Ochre / Limonite
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
mineral
Chert (and/or River Pebble)
Microcrystalline silica (SiO2)
sedimentary
Emerald In Matrix (Quartz/Calcite)
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
mineral
Chalcedony (Botryoidal)
Silicon Dioxide (SiO2)
mineral
Specular Hematite
Specularite (Fe2O3)
mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
River Quartzite (River Rock)
Quartzite (SiO2)
metamorphic
Sandstone (likely Graywacke or Arkose variant)
Clastic Sedimentary Rock (SiO2 based)
sedimentary
Quartz (specifically Clear Quartz or Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Amethyst Geode
Silicon Dioxide with impurities (SiO2)
mineral
Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Smoky Quartz (SiO2: Silicon Dioxide)
mineral
Pink Tourmaline (Rubellite)
Elbaite (Tourmaline group) - Na(Li,Al)3Al6(BO3)3Si6O18(OH)4
mineral
Agate (or Chalcedony)
Silicon Dioxide (SiO2)
mineral
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide impurities
mineral
Gossan (Iron Hat) with Quartz and Chlorite
Limonite/Goethite-rich Gossan (FeO(OH)·nH2O) with inclusions of Quartz and Chlorite
Mineral/Metamorphic Substrate
Decomposed Granite
Grano-diorite/Granite-residuum (SiO2 primary)
igneous
Quartz (Druzy or Geode fragment)
Silicon Dioxide (SiO2)
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Green Opal
Hydrated Silica (SiO2·nH2O)
mineraloid