Prehnite with Epidote inclusions
Prehnite: Ca2Al(AlSi3O10)(OH)2; Epidote: Ca2(Al,Fe)3(SiO4)3(OH)
Mineral
Category
Man Made Object (Coin)
Browse man made object (coin) specimens identified by the Rock Identifier community.
Turquoise color-bead and Hematite necklace
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Hematite (Fe2O3)
mineral
Fossilized Gastropod in Chert/Limestone
Internal mold of Gastropoda (Class) with CaCO3 or SiO2 mineral formula
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Limonite (Iron Ore)
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)
Mineral
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Crazy Lace Agate
Chalcedony (Silicon Dioxide, SiO2)
mineral
Chert (Chert / Flint nodule)
Silicon Dioxide (SiO2)
sedimentary
Greenstone / Diorite
Intermediate plutonic igneous rock
igneous
Green Fluorite
Fluorite (Calcium Fluoride) - CaF2
mineral
Hematite (Iron Ore)
Hematite (Fe2O3)
mineral
Carnelian Agate
Silicon Dioxide (SiO₂), a variety of Chalcedony
mineral
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions), SiO2
sedimentary
Citrine
Silicon Dioxide (SiO2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Banded Iron Formation (BIF)
Banded Iron Formation
Sedimentary Rock
Jade (Nephrite or Jadeite)
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (Na(Al,Fe3+)Si2O6)
Mineral
White Quartz
Quartz (SiO2)
Mineral
Bloodstone Jasper (Heliotrope)
SiO2 (Silicon Dioxide) - Cryptocrystalline Quartz
sedimentary
Red Jasper (possibly Brecciated Jasper or Bloodstone variety)
Jasper (Silicon Dioxide, SiO2)
sedimentary
Yellow Quartz (Citrine/Lemon Quartz)
Silicon Dioxide (SiO2)
mineral
Pegmatite (Granite Pegmatite)
Intrusive Igneous Rock (Granite Pegmatite)
igneous
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)
Igneous
Fluorite
Calcium Fluoride (CaF2)
mineral
Petrified Wood
Silicified wood, primarily composed of Quartz (SiO2)
Mineral, often found in sedimentary deposits
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Obsidian
Obsidian (Volcanic Glass)
igneous
Fossil Coral
Cnidaria fossil (often Calcium Carbonate / CaCO3)
sedimentary
Fossil Coral
Cnidaria Anthozoa (Fossilized)
sedimentary
Vesicular Basalt (River Rock)
Afanitic Vesicular Basalt
igneous
Jasper Agate (specifically Brecciated Jasper)
Silicon Dioxide (SiO2) with iron oxide and clay impurities
sedimentary
Chalcedony
Silicon Dioxide (SiO2)
mineral
Fossilized Crab Carapace (Concretion)
Decapoda (fossil), typically preserved in calcite or siderite concretion
sedimentary
Turquoise
Turquoise (Hydrated phosphate of copper and aluminium), CuAl6(PO4)4(OH)8·4H2O
mineral
Jasper (Red Chert)
Jasper (Silicon Dioxide, SiO2)
sedimentary
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Iron Ore / Ironstone Concretion
Mixture of iron oxide/hydroxide minerals, likely some combination of Hematite (Fe2O3), Goethite (α-FeOOH), and Limonite (a general term for hydrated iron oxides of variable composition) or potentially Bauxite (a mixture of aluminum hydroxides, often with iron oxides, (Al(OH)3) and FeO(OH)). The visual characteristics strongly suggest iron-rich material.
Mineral, specifically an iron ore
Jasper (Imperial Jasper style)
Silicon Dioxide (SiO2) with impurities
sedimentary