Limonite Concretion
Limonite (Hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)
sedimentary
Category
Mineral (Biogenic)
Browse mineral (biogenic) specimens identified by the Rock Identifier community.
Learn about Mineral (Biogenic) in the encyclopedia
View all →
Bauxite
AlOx(OH)3-2x (mixture of Gibbsite, Boehmite, and Diaspore)
sedimentary
Sandstone
Arenite
sedimentary
Native Copper
Native Copper (Cu)
mineral
Clear Quartz (Tumbled)
Silicon Dioxide (SiO2)
mineral
Fluorite (Purple/Blue variety)
Calcium Fluoride (CaF2)
mineral
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Sandstone (Banded)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Collection of Minerals and Ores
Various (e.g., Uraninite (U3O8), Carbon (C), Native Gold (Au), Hematite (Fe2O3), Galena (PbS), etc.)
mineral
Hematite Mineral Ore
Iron(III) oxide (Fe2O3)
mineral
Aquamarine
Beryl (Be3Al2Si6O18 with trace Fe2+)
Mineral
Epidote
Epidote (formula: Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
mineral
Diorite
Diorite (intermediate intrusive igneous rock)
igneous
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Gneiss
High-grade Metamorphic Gneiss
metamorphic
Epidote
Epidote Group (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
metamorphic
Sandstone Pebble
Arenite (SiO2 complex)
sedimentary
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Satin Spar (Gypsum)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
mineral
Satin Spar (Gypsum)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
mineral
Fluorite
Calcium fluoride (CaF2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Granite Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Fluorite
Calcium Fluoride (CaF2)
mineral
Sandstone (River Rock)
Arenite (composed primarily of SiO2)
sedimentary
Limonite (Ironstone)
Hydrated Iron Oxide (FeO(OH)·nH2O)
mineral
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
Mineral/Mineraloid within a rock matrix
Calcite
Calcite (Mineral, Calcium Carbonate - CaCO3)
Mineral
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Extrusive volcanic rock)
igneous
Pyrite
Iron Sulfide (FeS2)
mineral
Snowflake Obsidian
Volcanic Glass with Cristobalite Inclusions
igneous
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Limonite (often after Hematite or Goethite)
Limonite (FeO(OH)·nH2O)
mineral
Raw Fluorite
Calcium Fluoride (CaF2)
mineral
Quartz (specifically Clear and Rose Quartz)
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Titanium Aura Quartz
Titanium-coated Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral