Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
sedimentary
Category
Not A Rock
Browse not a rock specimens identified by the Rock Identifier community.
Emerald in Matrix
Beryl (Be3Al2Si6O18) containing Chromium/Vanadium impurities
mineral
Geode (unopened) or Calcareous Nodule
Siliceous or Calcareous Concretion/Nodule
sedimentary
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
Sandstone Concretion
Clastic sedimentary rock (primarily Quartz 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
Opalite
Man-made Glass (SiO2 + additives)
mineraloid (synthetic)
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
Granodiorite
Granodiorite (Intermediate to Felsic Intrusive Rock)
igneous
Quartz (specifically Clear Quartz or Rock Crystal)
Silicon Dioxide (SiO2)
mineral
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
Chalcedony Nodule (Agate/Chert)
Chalcedony (cryptocrystalline Silicon Dioxide, SiO2)
mineral
Green Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Pumice
Pumice (a highly vesicular volcanic glass)
igneous
Muscovite Mica (Golden/Yellow variety)
KAl2(AlSi3O10)(F,OH)2
mineral
Scoria (Lava Rock)
Vesicular Basalt / Scoria
igneous