Tufa (Vesicular Limestone)
Tufa (form of Calcium Carbonate, CaCO3)
sedimentary
Category
Organic (Geological Relative)
Browse organic (geological relative) specimens identified by the Rock Identifier community.
Basalt
Extrusive mafic igneous rock
igneous
Basalt
Extrusive mafic igneous rock
igneous
Basalt
Basalt (containing mainly Plagioclase feldspar and Pyroxene)
igneous
Ironstone Concretion / Goethite Nodules
Ironstone (composed primarily of Goethite FeO(OH) and Limonite)
sedimentary
Bog Iron / Limonite Concretion
Goethite/Limonite mixture (FeO(OH)·nH2O)
sedimentary
Basalt
Basalt (Aphanitic Mafic Igneous)
igneous
Mother of Pearl and Onyx
Aragonite (Mother of Pearl) and Chalcedony (Onyx)
mineral
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
igneous
Marble
Metamorphosed Limestone (principally CaCO3)
metamorphic
Basalt
Mafic Volcanic Rock
igneous
Moqui Marble (Shaman Stone)
Ironstone Concretion (Fe2O3) - primarily Hematite or Goethite shell with Sandstone core
sedimentary
Pumice
Vesicular Rhyolite or Andesite (Amorphous volcanic glass)
igneous
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Basalt
Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)
igneous
Chert (Jasper/Flint variety)
Microcrystalline quartz (SiO2)
sedimentary
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Banded Chert
Silicon Dioxide (SiO2)
sedimentary
Chert (Jasper variation)
Chert (Microcrystalline Silicon Dioxide, SiO2)
sedimentary
Orange Calcite (Polished Sphere)
Calcium Carbonate (CaCO3)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Basalt
Basalt (Mafic volcanic rock)
igneous
Limonite and Goethite encrusted Chert/Ironstone
Hydrated Iron Oxide (FeO(OH)·nH2O) with cryptocrystalline Silica (SiO2)
sedimentary
Basalt Pebble
Basalt (Extrusive Mafic Igneous)
igneous
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Glauconitic Sandstone
Glauconitic Quartz Arenite
sedimentary
Chert (specifically Flint or Jasper variant)
Microcrystalline quartz (SiO2)
sedimentary
Chert (Smooth River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Basalt
Mafic extrusive volcanic rock (composed primarily of Plagioclase feldspar and Pyroxene)
igneous
Chalcedony (variations like Agate or Jasper)
Chalcedony (SiO₂ - microcrystalline quartz)
Mineral
Basalt
Extrusive Mafic Igneous Rock (composed primarily of plagioclase feldspar and pyroxene)
igneous
Green Aventurine
Aventurine (a variety of Quartz, SiO2)
Mineral
Green Fluorite (Beaded)
Fluorite (Calcium Fluoride, CaF2)
mineral
Ammonite Fossil (Polished Half / Cleoniceras)
Ammonoidea (Subclass), often Cleoniceras genus; fossilized with Calcite (CaCO3) and Aragonite
Sedimentary
Moss Agate
Silicon Dioxide with inclusions (SiO2 + Fe/Mn/Mg)
mineral
Sand Dollar Fossil (Echinoidea)
Class Echinoidea (likely order Clypeasteroida), CaCO3 (Calcite)
sedimentary
Pumice
Pumice (volcanic glass formed of highly vesicular rough textured rock)
igneous
Amber
Succinite (Approximate formula: C10H16O)
mineral
Unknown Organic Object (likely a berry or fruit)
Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.
Organic Material (likely a fruit or berry)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral