Limonite (Ironstone)
Limonite (FeOO·nH2O)
mineral
Category
Not A Natural Rock
Browse not a natural rock specimens identified by the Rock Identifier community.
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Hag Stone
Perforated Sedimentary Rock
sedimentary
Opalite (Synthetic Moonstone/Opal)
Synthetic Silica Glass
mineraloid (synthetic)
Dyed Agate
Silicon Dioxide (SiO2) with artificial pigment
sedimentary
Limonite (Iron Stone/Goethite)
Limonite (mixture of hydrated iron oxides, primarily Goethite: α-FeO(OH))
mineral
Tektite
Natural impact glass
meteorite
Sandstone
Arenite
sedimentary
Limonite (Iron Ore)
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Dragon Vein Agate
Silicon dioxide / Chalcedony (with heat/dye treatment) SiO2
gemstone
Unknown Rock Fragment
Undetermined
igneous
Lightning Stone / Fulgurite-impregnated or Septarian-like Agate
Silicon dioxide (Quartz/Chalcedony) with host rock matrix
sedimentary
Opalite
Synthesized glass / Silicon dioxide glass
gemstone
Sandstone
Arenite (Clastic Sedimentary Rock)
sedimentary
Polished agate pendant
Microcrystalline quartz (chalcedony), SiO₂; agate is banded chalcedony
mineral
Herkimer Diamond
Quartz (Silicon Dioxide) - SiO2
mineral
Sandstone
Arenite (SiO2 based typically)
sedimentary
Kimberlite
Ultramafic igneous rock
igneous
Vesicular Basalt / Scoria pebble
Extrusive igneous rock with amygdaloidal infilling
igneous
Pearl oyster shell with natural pearls
Molluscan shell, likely Pinctada spp.; pearls are aragonite (CaCO₃)
fossil
Limonite / Ironstone
Hydrated Iron Oxide (FeO(OH)·nH2O)
mineral
Shale
Laminated Mudstone (Shale)
sedimentary
Small rounded stone, likely a pebble
Unidentified fine-grained lithic pebble; image alone does not support a reliable mineral or rock-species identification
sedimentary
Amethyst beads
Amethyst, purple quartz (SiO₂)
gemstone
Likely weathered iron-rich rock or slag fragment
Indeterminate; possibly limonite/goethite-bearing rock (FeO(OH)·nH₂O) or industrial iron slag
mineral
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Sandstone
Clastic sedimentary rock (quartz arenite)
sedimentary
Sandstone (with vugs or solution cavities)
Arenite (primarily Quartz and Feldspar with CaCO3 or SiO2 cement)
sedimentary
Opalite (a synthetic glass)
Silicon Dioxide (SiO2) with various additives; not a true mineral but a man-made gem simulant
Mineral Simulant (Synthetic Glass)
Small pale stone (unidentified)
Undetermined; image detail is insufficient for reliable identification
mineral
Yellow-brown stone or mineral fragment
Unidentified; the image does not show enough detail for a reliable identification
mineral
Small rounded pebble; specific identification uncertain
Indeterminate lithic fragment; mineral composition cannot be determined from the image
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Small rounded pebble, possibly quartz-rich stone
Indeterminate; likely quartz/quartzite or a weathered feldspathic pebble
igneous
Quartz Vein in Host Rock
Silicified matrix with hydrothermal quartz (SiO2)
igneous
River Cobble (Basaltic/Andesitic)
Mafic to Intermediate Volcanic Rock
igneous
Agate
Silicon dioxide (Chalcedony), SiO2
sedimentary
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
mineral
Limonite (Pseudomorph after Pyrite/Marcasite)
Hydrated Iron Oxide (FeO(OH)·nH2O)
mineral
River Pebble
Quartzite / Siliciclastic Rock
sedimentary
Rounded quartz-rich river pebble
Likely quartz-bearing rock; exact lithology cannot be determined from the photograph
igneous
Conglomerate
Clastic Sedimentary Rock
sedimentary