Chert (Flint nodule)
Silicon dioxide (SiO2)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Chert (Flint nodule)
Silicon dioxide (SiO2)
Citrine
Silicon Dioxide (SiO2)
Peach Moonstone
Orthoclase Feldspar (KAlSi3O8) with inclusions
Veined Pebble (likely a Quartz-Veined Pebble)
Pebble with Mineral Vein (e.g., Quartz Vein in a Chert/Mudstone Pebble)
Banded Agate (Polished Slice)
Chalcedony (cryptocrystalline Quartz), SiO2
Drill Core Samples (Varied Lithology)
Multi-lithological core samples (containing potential granite, marble, and phyllite/schist sequence)
Gneiss
High-grade metamorphic rock (Gneiss)
Concretion
Various mineral compositions, typically carbonate or iron oxide cemented sediment
Quartz Geode
Silicon Dioxide (SiO2)
Citrine
Quartz (SiO₂) variety
Tiger's Eye (Brown/Dark variety)
Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)
Petrified Wood
Silicified Wood (SiO2)
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Volcanic Rock)
Schist
Mica Schist (Medium-grade Metamorphic Rock)
Glauconitic Sandstone (or Greensand)
Glauconitic Siliciclastic Rock (Containing (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals, Mg3Si2O5(OH)4)
Fairburn Agate
Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Rhodochrosite
Manganese carbonate (MnCO3)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Vesicular Basalt (or Scoria)
Vesicular Basalt (Aphanitic-vesicular volcanic rock)
Moonstone
Potassium Aluminum Silicate (KAlSi3O8)
Obsidian
Volcanic Glass (Extrusive Igneous Rock, primarily SiO2)
Amethyst
Silicon dioxide (SiO2)
Olivine (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4
Basalt with Scoria
Amygdaloidal Basalt / Vesicular Basalt
Amethyst
SiO2 (Silicon Dioxide) - a variety of Quartz
Agate
Agate (Silicon Dioxide, SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
Sandstone (Banded)
Clastic sedimentary rock (primarily SiO2)
Amazonite
Potassium Aluminum Silicate (KAlSi3O8)
Alexandrite
Chrysoberyl (BeAl2O4)
Amethyst
SiO2 (Silicon Dioxide with iron impurities)
Prasiolite (Green Quartz)
Silicon Dioxide (SiO2) with iron impurities
Carnelian
Chalcedony (SiO2) with Iron Oxide impurities
Aquamarine
Beryl (Be3Al2Si6O18 with Fe2+ impurities)
Blue Chalcedony
Chalcedony (SiO2)
Amazonite
K(AlSi3O8)
Amazonite
Microcline (KAlSi3O8)
Amethyst
Silicon Dioxide (SiO2) with iron impurities