Chert (Field Stone/Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Category
Man Made (Synthetic Rock)
Browse man made (synthetic rock) specimens identified by the Rock Identifier community.
Brachiopod Fossil in Shale
Phylum Brachiopoda (often species of Order Spiriferida or Rhynchonellida)
sedimentary
Jasper (Chert)
Silicon Dioxide (SiO2)
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Extrusive volcanic rock)
igneous
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Limonite (Iron Ore)
Goethite and related iron hydroxides (FeO(OH)·nH2O)
mineral
Basalt Porphyry
Porphyritic Basalt
igneous
Sandstone
Arenite (predominantly Quartz Sandstone)
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
Granite
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Granite Gneiss
Felsic Gneiss
metamorphic
Sandstone (Ferruginous)
Arenite (Fe2O3 enriched)
sedimentary
Serpentinite (Serpentine Rock)
Primarily composed of serpentine group minerals, such as antigorite, chrysotile, and lizardite. Chemical formula for serpentine minerals is (Mg,Fe)3Si2O5(OH)4.
Metamorphic
Quartz on Greenstone
Silicon Dioxide (SiO2) on Altered Igneous Geologic Unit
metamorphic
Sandstone
Arenite (SiO2 primarily)
sedimentary
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)
Scoria (with likely iron oxidation)
Scoria (Basaltic Scoria)
igneous
River Pebbles and Quartz
Mixed Igneous, Sedimentary, and Metamorphic Rocks (Silicon Dioxide SiO2 dominant)
mixed
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
metamorphic
Quartzite Pebble (River Rock)
Quartzite (mainly SiO2)
metamorphic
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
sedimentary
Sandstone (Quartzose Sandstone)
Clastic Terrigenous Sedimentary Rock (primarily SiO2)
sedimentary
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
igneous
Granite Cobble
Plutonic Igneous Rock (Granitic)
igneous
Jasper (Yellow/Brown variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Sandstone
Arenite
sedimentary
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Yellow Jasper
Silicon Dioxide (SiO2) - Impure Cryptocrystalline Quartz
sedimentary
Sandstone (clastic)
Clastic Sedimentary Rock (primarily composed of SiO2)
sedimentary
Vesicular Basalt (or Scoria)
Vesicular Basalt
igneous
Basalt Scoria
Vesicular Basalt
igneous
Moss Agate
Silicon Dioxide (SiO2) with inclusions
mineral
Quartz (Milky/Common Quartz)
Silicon Dioxide (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