Petrified Wood
Silicified Wood (SiO2)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
Graphite
Graphite (C)
Chert (and Fossilized Brachiopod shell)
Sedimentary Cryptocrystalline Quartz (SiO2)
Fluorite with Quartz coating
Calcium Fluoride (CaF2) with Silicon Dioxide (SiO2)
Gold in Quartz Matrix
Native Gold (Au) with Quartz (SiO2) and Slate/Shale
Amygdaloidal Basalt with Epidote/Chlorite
Basalt (containing (Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)))
Granite
Intrusive Felsic Igneous Rock
Agate
Silicon Dioxide (SiO2)
Mexican Crazy Lace Agate
Silicon Dioxide (SiO2) with iron and aluminum inclusions
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Extrusive volcanic rock)
Rhodonite
Manganese silicate (Mn,Fe,Mg,Ca)SiO3
Banded Gneiss
Gneiss (Metamorphic Rock)
Granite
Granite (Felsic Plutonic Rock)
Amygdaloidal Basalt
Amygdaloidal Basalt (with secondary mineral infilling)
Note regarding baguette production (not a rock)
Digital text image - Somali language
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Red Jasper
Silicon dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Basalt with Quartz/Calcite Vein
Amygdaloidal Basalt (matrix) with Mineral Vein filling
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 based)
Shatter Cone
Impactite (Shatter Cone texture)
Quartz Crystal (specifically a Double-Terminated variety)
Silicon Dioxide (SiO2) - Low Quartz
Sandstone
Arenite (primarily SiO2)
Peridot
Olivine (Mg, Fe)₂SiO₄
Amygdaloidal Basalt
Amygdaloidal Mafic Volcanic Rock
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Greenstone (Greywacke or Nephrite Jade variant)
Metamorphosed mafic igneous or sedimentary rock (e.g., Actinolite-Chlorite Schist)
Calcite (Yellow/Orange variety - sometimes called Honey Calcite)
Calcite
Tanzanite
Blue Zoisite (Ca2Al3(SiO4)(Si2O7)O(OH))
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Druzy Quartz on Limestone
Silicon Dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2)
Granite
Granite (a plutonic rock)
Biotite Schist
Biotite Schist (Rich in K(Mg,Fe)3AlSi3O10(OH)2)
Quartz (milky quartz variety)
Quartz (SiO₂)
Aquamarine
Beryl (Be3Al2Si6O18 with trace Fe2+)
Sandstone (Banded)
Clastic Sedimentary Rock: Arenite
Petrified Wood
Silicified wood (principally Silicon Dioxide, SiO2)
Jade
Jadeite or Nephrite
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Orthoclase Feldspar with Quartz
Orthoclase (KAlSi3O8)