Chert (River Pebble)
Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Sedimentary (Secondary Mineral) Within Igneous
Browse sedimentary (secondary mineral) within igneous specimens identified by the Rock Identifier community.
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Bloodstone (Heliotrope)
Silicon Dioxide (SiO2) with inclusions of Chlorite or Actinolite
sedimentary
Turquoise in Matrix
Hydrous phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O
mineral
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
mineral
Green Aventurine (Green Quartzite)
Silicon Dioxide (SiO2) with inclusions of Fuchsite mica
metamorphic
Blue Calcite (commonly sold as Caribbean Calcite)
Calcium Carbonate (CaCO3)
mineral
Blue Calcite
Calcium Carbonate (CaCO3)
mineral
Weathered basalt fragment
Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, with possible olivine and iron-oxide alteration
igneous
Gneiss
Gneiss
metamorphic
Dyed Cracked Agate
Silicon Dioxide (Quartz variety, SiO2)
gemstone
Limonite
FeO(OH)•nH2O
mineral
Limonite
FeO(OH)•nH2O
mineral
Gneiss
Gneiss
metamorphic
Limonite
FeO(OH)•nH2O
mineral
Amethyst and Calcite collection
Silicon Dioxide (SiO2) and Calcium Carbonate (CaCO3)
mineral
Vesicular basalt (lava rock)
Vesicular basalt, composed mainly of plagioclase, pyroxene, and often olivine
igneous
Gneiss
Gneiss
metamorphic
Limonite / Ironstone
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
mineral
Amygdaloidal Basalt
Mafic extrusive igneous rock with secondary mineral infillings
igneous
Chert (Pebble)
Microcrystalline to Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper influence)
Microcrystalline Quartz (SiO2)
sedimentary
Variscite (in Matrix)
Hydrated aluminum phosphate (AlPO4·2H2O)
mineral
Limonite stained Sandstone
Sedimentary rock with Goethite/Limonite (FeO(OH)·nH2O)
sedimentary
Jasper (or possibly Agate/Chalcedony) beads
SiO2 (Silicon Dioxide)
mineral
Pyrite Cube in Matrix
Iron Sulfide (FeS2)
mineral
Banded Chert (Agate/Jasper blend)
Microcrystalline Quartz (SiO2)
sedimentary
Ocean Jasper
Orbicular Jasper (Silicon Dioxide, SiO2)
sedimentary
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Limonite with Quartz
Hydrated Iron Oxide Hydroxide with Silicon Dioxide (FeO(OH)·nH2O + SiO2)
mineral
Limonite
FeO(OH)·nH2O
mineral
Weathered iron-rich rock (likely ironstone or altered basalt)
Probable limonite/goethite-bearing basalt or ironstone; exact identification requires testing
igneous
Massive White Quartz
Silicon Dioxide (SiO2)
mineral
Limonite
FeO(OH)·nH2O
mineral
Blue and White Quartz
Crystalline Silicon Dioxide with inclusions (SiO2)
mineral
Gneiss
Metamorphic Gneiss
metamorphic
Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Limonite
FeO(OH)•nH2O
mineral
Vesicular basalt with secondary zeolite/mineral crusts
Basalt, chiefly plagioclase–pyroxene ± olivine; cavities partly filled by zeolites or calcite
igneous
Polished volcanic scoria or vesicular basalt
Vesicular basalt; primarily plagioclase, pyroxene, and iron-rich glass/oxides
igneous
Jasper with Quartz Veining
Microcrystalline quartz (SiO2) with iron oxide impurities
sedimentary
Red Jasper (possibly with Quartz or Hematite)
Silicon Dioxide (SiO2) with iron oxide impurities
sedimentary or metamorphic
Pale blue-green altered volcanic rock, likely basalt
Altered basalt (fine-grained plagioclase–pyroxene rock with secondary zeolite/chlorite minerals)
igneous