Basalt
Basalt (Aphanitic mafic volcanic rock)
igneous
Category
Not A Rock (Synthetic Material)
Browse not a rock (synthetic material) specimens identified by the Rock Identifier community.
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
igneous
Basalt
Basalt (Aphanitic Mafic Volcanic Rock)
igneous
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Granite (specifically Rapakivi Granite)
Phaneritic Felsic Igneous Rock (Granite)
igneous
Quartzite
Quartzite (SiO2)
metamorphic
Sandstone
Arenite (a specific type of sandstone with less than 15% matrix)
Sedimentary rock
Chert (White/Gray variety)
Chert (SiO2)
sedimentary
Sandstone (with Iron Staining)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
sedimentary
Porphyritic Basalt (Peanut Obsidian/Star Galaxy-style)
Porphyritic Basalt (Silica-rich Volcanic Rock)
igneous
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Shale or Siltstone
Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)
sedimentary
Chalcedony (Botryoidal or Agate nodule)
Silicon Dioxide (SiO2)
mineral
Brachiopod Fossil in Limestone
Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)
sedimentary
Snowflake Obsidian (or similar porphyritic volcanic rock)
Obsidian with Spherulites (if glassy), or Porphyritic Rhyolite/Andesite (if crystalline groundmass)
igneous
Obsidian
Volcanic Glass (Extrusive Igneous Rock, primarily SiO2)
igneous
Diorite
Phaneritic Intermediate Plutonic Rock (Diorite)
igneous
Ferruginous Conglomerate
Ferruginous Conglomerate (Clastic Sedimentary Rock)
sedimentary
Granite River Pebble
Phaneritic Felsic Igneous Rock (Granite)
igneous
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
mineral
Olivine in Basalt (Peridot)
Magnesium Iron Silicate (Mg, Fe)2SiO4 in Vesicular Basalt
igneous
Chert (Flint)
Microcrystalline quartz (SiO2)
sedimentary
Sandstone (with Iron Staining)
Clastic sedimentary rock (High Silica / Iron Oxide)
sedimentary
Ferruginous Sandstone (Gozzan)
Iron-rich clastic sedimentary rock with Limonite/Goethite
sedimentary
Slate
Metamorphosed Shale (Fine-grained Foliated Metamorphic Rock)
metamorphic
Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Ventifact
Eolian Ventifact (often composed of basalt, chert, or quartzite)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Diorite (Salt and Pepper Rock)
Phaneritic Plutonic Diorite (Plagioclase Feldspar + Amphibole/Biotite)
igneous
Nuummite
Nuummite (Orthoamphibole rock composed of Anthophyllite and Gedrite, (Mg,Fe)7Si8O22(OH)2)
metamorphic
Red Sandstone
Arenite with Hematite cementation
sedimentary
Jasper Conglomerate (Puddingstone)
Siliceous Conglomerate (Quartz and Jasper clasts in a fine-grained matrix)
sedimentary
Diorite
Diorite
igneous
Ferruginous Breccia
Breccia with Iron-rich (Hematite/Goethite) Matrix
sedimentary
Coquina
Bioclastic Limestone
sedimentary
Basalt
Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)
igneous
Coquina
Bioclastic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
River Rock / Stream Pebble
Fluvial Clast / Rounded Sedimentary Particle
Sedimentary Rock (possibly composed of various minerals)
Siltstone/Sandstone (possibly Wonderstone or Picture Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide inclusions)
Sedimentary
Pink Granite
Felsic Plutonic Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)
igneous