Obsidian
Volcanic Glass (SiO2)
igneous
Category
Mineral Like Biological Tissue
Browse mineral like biological tissue specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Amethyst (Tumbled Quarz)
Silicon Dioxide (SiO2) with iron impurities
mineral
Quartz / Clear Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Botryoidal Chalcedony (likely Desert Rose/Agatized Geode Crust)
Silicon Dioxide (SiO2)
mineral
Obsidian
Obsidian (Volcanic Glass)
Igneous
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Tourmalinated Quartz
Silicon Dioxide (SiO2) with inclusions of Schorl (NaFe2+3Al6Si6O18(BO3)3(OH)3OH)
mineral
Malachite
Malachite (Copper Carbonate Hydroxide) - Cu2CO3(OH)2
Mineral
Silver Sheen Obsidian
Volcanic Glass (Amorphous Silicon Dioxide - SiO2 with impurities)
igneous
Green Quartzite
Quartzite (SiO2)
metamorphic
Pink Sapphire
Corundum (Al2O3) with Chromium/Iron/Titanium trace impurities
mineral
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Mineral
Quartz (specifically Milky or Clear Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz / Milky Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Sunstone
Oligoclase (Plagioclase Feldspar Group) - (Ca, Na)(Al, Si)4O8
mineral
Quartz nodule (River pebble)
Silicon Dioxide (SiO2)
mineral
Chert (often called Flint or Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Slag (Industrial Glass Slag)
Amorphous Silicate Glass (often containing Al, Ca, Mg, and Ti oxides)
Mineraloid (Industrial byproduct)
Sandstone Concretion
Clastic Sedimentary Concretion (primarily SiO2 with Fe2O3 cement)
sedimentary
Specular Hematite (Specularite)
Iron Oxide (Fe2O3)
mineral
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions of Chlorite, Manganese, or Iron
mineral
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminum phosphate)
mineral
Conglomerate
Conglomerate (Sedimentary Clastic Rock)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity
mineral
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2)
igneous
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Septarian Nodule or Mud Crack Fossil
Septarian Nodule (Concretion)
sedimentary
Mica Schist
Mica Schist (Quartz-Biotit-Muscovite Schist)
metamorphic
Native Copper in Basalt
Cuprum (with Host Basalt)
igneous
Graphite-veined Quartzite
Meta-sedimentary Quartzite with Carbonaceous/Graphitic Inclusions (SiO2 + C)
metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gneiss
Gneiss
metamorphic
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
mineral
Gneiss
Gneiss
metamorphic
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Collection of Minerals and Ores
Various (e.g., Uraninite (U3O8), Carbon (C), Native Gold (Au), Hematite (Fe2O3), Galena (PbS), etc.)
mineral
Sandstone (with Iron Staining)
Clastic sedimentary rock (SiO2 with Fe2O3 oxides)
sedimentary
Flower Agate (Cherry Blossom Agate)
Chalcedony (SiO2) with Opaque Inclusions
mineral