Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Diorite (possibly fine-grained variety or a related intermediate intrusive rock like a felsic gabbro or a dark granodiorite)
Diorite (Igneous rock, intrusive, intermediate composition)
Shale
Fissile mudstone (Shale)
Sunstone
Oligoclase or Andesine (Labradorite) Feldspar (Na,Ca)(Si,Al)4O8
Serpentine (variety: Serpentine Rock)
Antigorite, Lizardite, or Chrysotile; formula generally (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4
Smoky Quartz
Silicon Dioxide (SiO2)
Carnelian
Carnelian (subset of Chalcedony); SiO2 with Iron Oxide impurities
Petrified Wood
Silicified wood, primarily composed of Quartz (SiO2)
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
Jade (Nephrite or Jadeite)
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (Na(Al,Fe3+)Si2O6)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Sandstone (Picture Sandstone)
Arenite (primarily SiO2)
Banded Agate (specifically Moss Agate or Plume Agate variety)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Rhodonite
Rhodonite; (Mn,Fe,Mg,Ca)SiO3
Shale
Shale (Lutite)
Quartz Pebble
Silicon Dioxide (SiO2)
Blue Chalcedony and Picture Jasper Beads
Blue Chalcedony (SiO2), Picture Jasper (SiO2)
Sunstone
Heliolite (Sodium Calcium Aluminum Silicate with Iron or Copper inclusions)
Orange Calcite
Calcium Carbonate (CaCO3)
Smoky Quartz
Silicon Dioxide (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Quartz (Milky Variant)
Silicon Dioxide (SiO2)
Rose Quartz
Silicon Dioxide (SiO2) with trace titanium, iron, or manganese
Smoky Quartz
Silicon Dioxide (SiO2)
Red Jasper
Silicon dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)
Silty Shale
Silty Shale (Fissile Sedimentary Rock)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Shale (with Iron Oxide staining)
Fissile Mudstone (primarily Quartz and Clay minerals)
Baltic Amber
Succinite (Polmerized conifer resin)
Chert with Asphaltum (or Tar)
Silica (SiO2) with natural Bitumen/Asphaltum
Scoria
Vesicular Basalt / Scoriaceous Basalt
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Milky Quartz
Silicon Dioxide (SiO2)
Yellow Quartz (Citrinated Quartz)
Silicon Dioxide (SiO2)
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
Chrysoprase
Silicon Dioxide (Nickel-bearing Chalcedony) - SiO2
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Greisen (Quartz-Muscovite-Turretine Rock)
Greisen
Sandstone
Arenite (SiO2 based with various mineral cements)
Aventurine
Aventurine Quartz (SiO2 with inclusions)