Ironstone Concretion (Limonite/Hematite Nodules)
Ironstone (principally Limonite FeO(OH)·nH2O or Hematite Fe2O3 mixed with silica/clay)
sedimentary
Category
Not A Geological Specimen
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Asphalt (Road Aggregate)
Asphalt concrete / Bituminous mixture
anthropogenic sedimentary (technolith)
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial Byproduct)
mineraloid
Banded Iron Formation (BIF)
Banded Iron Formation
Sedimentary Rock
Black Tourmaline (Schorl)
Schorl (Sodium Iron Aluminum Borosilicate Hydroxide), NaFe2+3Al6(Si6O18)(BO3)3(OH)3OH
mineral
Concretion or Geode (unbroken)
Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.
Sedimentary rock (specifically a concretion or possibly a geode)
Diamond (in a jewelry setting)
Cubic Carbon (C)
mineral
Blue Chalcedony and Picture Jasper Beads
Blue Chalcedony (SiO2), Picture Jasper (SiO2)
Mineral
Granite
Phaneritic intrusive igneous rock (primarily SiO2)
igneous
Diamond
Diamond (pure Carbon, C)
mineral
Diamond (in jewelry setting)
Adamantine Carbon (C)
mineral
Diamond (set in Gold)
Diamond (pure carbon, C)
mineral
Jewelry (Ring)
This image does not contain a rock, mineral, or geological specimen. The object in the image is a piece of jewelry, specifically a ring with a pentagram and what appears to be a red gem or stone set in the center.
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Organic Structure (Not a Rock)
Quartz in Limonite-rich Matrix
Silicon Dioxide (SiO2) with Goethite/Limonite FeO(OH)·nH2O
Mineral in Sedimentary/Secondary host
Anthropogenic Heat Source (Electronic/Industrial Interface)
Thermal IR emission (Electronic infrastructure)
not a rock or mineral
Goethite / Limonite Gossan
Hydrated Iron Oxide (FeO(OH))
sedimentary
Dyed Pumice
Vesicular Rhyolite (Artificial Coloration Addition)
igneous
Limonite Concretion
FeO(OH)·nH2O (Hydrated Iron Oxide)
sedimentary
Opalite
Opalescent Glass (SiO2 + coloring agents)
Mineral (Synthetic/Man-made)
Limonite (Gossan)
FeO(OH)·nH2O (Hydrated Iron Oxide)
mineral
K2 Jasper (K2 Granite)
Azurite in Granite (Al2Cu3(CO3)2(OH)2 in NaAlSi3O8)
igneous
Limonite Concretion
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
sedimentary
Opalite
Man-made Glass (Synthetic Opalized Glass)
mineral
Limonite (after Pyrite Pseudomorph)
Limonite (Hydrated Iron Oxide Mixture, FeO(OH)·nH2O)
mineral
Opalite (a synthetic glass)
Silicon Dioxide (SiO2) with various additives; not a true mineral but a man-made gem simulant
Mineral Simulant (Synthetic Glass)
Man-made Blank Ammunition (Brass)
CuZn (Cartridge Brass - roughly 70% Copper, 30% Zinc)
Anticrystalline / Synthetic Alloy
Opalite
Synthetic Fluorescent Glass (SiO2 + impurities)
mineraloid (synthetic)
Glacial Granite with Epidote
Granite featuring Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
igneous
Concretion
Septarian Concretion (Fragmentary)
sedimentary
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Moqui Marble
Iron Oxide Concretion (Limonite/Hematite shell with Sandstone core)
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Specular Hematite with Quartz and Limonite
Hematite (Fe2O3) with Quartz (SiO2) and Limonite (FeO(OH)·nH2O)
Mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Painted River Rock
Anthropogenic-modified Siliciclastic Sedimentary Rock
Sedimentary
Fossilized Shark Tooth (Sand Tiger)
Carcharias taurus (fossil specimen)
sedimentary
Gold Ore in Quartz
Auriferous Quartz (Au + SiO2)
igneous
Botryoidal Agate
Silicon Dioxide (SiO2)
mineral
Petrified Wood (Jet or Coalified Wood appearance)
Silicified wood (principally SiO2) or Carbonized Wood
sedimentary