Granite
Granite (a felsic intrusive igneous rock)
Igneous Rock
Category
Mineral, Specifically A Detrital Grain
Browse mineral, specifically a detrital grain specimens identified by the Rock Identifier community.
Dark Igneous Rock (Likely Basalt or Diabase)
Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.
Igneous
Banded Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Yellow Quartzite (River Pebble)
Quartzite (primarily Silicon Dioxide, SiO2)
metamorphic
Basalt
Basalt (dominated by plagioclase feldspar and pyroxene)
igneous
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Quartzite
Quartzite
Metamorphic rock
Chert (specifically Jasper/Carnelian variety)
Microcrystalline quartz (SiO2)
sedimentary
Garnet (likely Almandine or a blend)
Garnet group: X3Y2(SiO4)3, where X can be Ca, Mg, Fe2+, Mn2+ and Y can be Al, Fe3+, Cr3+. Given the dark, somewhat reddish-brown appearance in the image, it's likely Almandine (Fe3Al2(SiO4)3) or a mix with other iron-rich garnets.
Mineral
Sandstone (Ferruginous)
Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)
sedimentary
White Quartzite
Quartzite (primarily SiO2 - Silicon Dioxide)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Sandstone
Arenite (primarily SiO2)
sedimentary
Mookaite (Mookaite Jasper)
Silicified Radiolarite (SiO2 with iron oxides)
sedimentary
Obsidian (specifically Silver Sheen Obsidian)
Volcanic Glass (approx. 70–75% SiO2 plus MgO, Fe3O4)
igneous
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
sedimentary
Yellow Jasper
Cryptocrystalline quartz (SiO2) with iron inclusions
sedimentary
Chert / Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Pink/Red variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Chert Pebble/Nodule
Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)
Sedimentary
Banded Calcite or Travertine
Calcium Carbonate (CaCO3)
Sedimentary
Sandstone (Quartzose)
Arenite (SiO2 based)
sedimentary
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 principal composition)
sedimentary
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
metamorphic
Sandstone
Arenite
sedimentary
Fossil Coral (Petoskey Stone or Favosites)
Favosites (specifically Hexagonaria percarinata if silica-replaced Michigan type)
sedimentary
Red Sandstone
Arenite (with Iron Oxide)
sedimentary
Basalt with Plagioclase Phenocrysts
Porphyritic Basalt
igneous
Chert (specifically Jasper or Flint variant)
Cryptocrystalline Quartz (SiO2)
sedimentary
Green Aventurine
Aventurine (a variety of Quartz, SiO2)
Mineral
Quartzite Pebble
Metamorphosed Sandstone (SiO2)
metamorphic
Gneiss (specifically Granitic Gneiss)
Gneissic Metamorphic Rock
metamorphic
Chert (specifically Banded Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (specifically Banded Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Ferrocoke or Slag
Anthropogenic pyrometallurgical residue
igneous
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Ocean Jasper (Orbicular Jasper)
Silicon Dioxide (SiO2)
Sedimentary Rock
Chert (Smooth River Pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Smoky variety)
Microcrystalline Quartz (SiO2)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite/Limonite)
sedimentary
Fossil Coral
Scleractinia (fossilized calcium carbonate)
sedimentary