Basalt
Extrusive mafic igneous rock
igneous
Category
Not A Rock (Man Made Polymer)
Browse not a rock (man made polymer) specimens identified by the Rock Identifier community.
Sandstone (Ferruginous)
Arenite (Fe2O3 enriched)
sedimentary
Sandstone (Pebble/Cobble)
Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)
Sedimentary
Sandstone
Arenite (predominantly Quartz Sandstone)
sedimentary
Granite
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Granite Gneiss
Felsic Gneiss
metamorphic
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Basalt
Basalt (principally Plagioclase and Pyroxene)
igneous
Granitic Pegmatite
Coarse-grained Igneous Rock (Granitic composition: KAlSi3O8, SiO2)
igneous
Rose Quartz
Silicon Dioxide (SiO2)
mineral
Jasper with Quartz inclusions
Silicon Dioxide (SiO2) with impurities
sedimentary
Jasper with Quartz Veining
Silicon Dioxide (SiO2) - Opaque cryptocrystalline variety of Quartz
sedimentary
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
mineral
Mixed Tumbled Gemstones and River Rocks
Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)
Mixed (Igneous, Sedimentary, Metamorphic, and Minerals)
River Pebbles and Quartz
Mixed Igneous, Sedimentary, and Metamorphic Rocks (Silicon Dioxide SiO2 dominant)
mixed
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
sedimentary
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
metamorphic
Quartzite Pebble (River Rock)
Quartzite (mainly SiO2)
metamorphic
Sandstone (Quartzose Sandstone)
Clastic Terrigenous Sedimentary Rock (primarily SiO2)
sedimentary
Scoria (with likely iron oxidation)
Scoria (Basaltic Scoria)
igneous
Yellow Jasper
Silicon Dioxide (SiO2) - Impure Cryptocrystalline Quartz
sedimentary
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
igneous
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Jasper (Yellow/Brown variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Sandstone
Arenite
sedimentary
Granite Cobble
Plutonic Igneous Rock (Granitic)
igneous
Sandstone (clastic)
Clastic Sedimentary Rock (primarily composed of SiO2)
sedimentary
Vesicular Basalt (or Scoria)
Vesicular Basalt
igneous
Chert (Common Opal/Agate mixture)
Microcrystalline Quartz (SiO2)
sedimentary
Tiger's Eye (Rough)
Pseudomorph of Quartz after Crocidolite (SiO2)
mineral
Agate Geode / Nodular Chalcedony
Silicon Dioxide (SiO2) with impurities
mineral
Gastropod Steinkern (Internal Mold Fossil)
Gastropoda (Class); Internal mold or 'Steinkern' composed of Calcium Carbonate (CaCO3) or Sedimentary matrix
sedimentary
Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Basalt Scoria
Vesicular Basalt
igneous
Moss Agate
Silicon Dioxide (SiO2) with inclusions
mineral
Quartz (Milky/Common Quartz)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Quartz on Greenstone
Silicon Dioxide (SiO2) on Altered Igneous Geologic Unit
metamorphic
Basalt (Polished River Stone)
Mafic Volcanic Rock (primarily Plagioclase and Pyroxene)
Igneous
Quartzite with Iron Inclusions
Metamorphic Quartzite (SiO2 with Fe2O3 trace impurities)
metamorphic