Obsidian
Volcanic Glass (SiO2)
Category
Browse non geological specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (SiO2)
Limonite
FeO(OH)·nH2O (Hydrated iron oxide)
Obsidian
Obsidian (volcanic glass), predominantly amorphous SiO₂
Amethyst
SiO2 (Silicon Dioxide)
Titanium-coated Metal Cube (Man-made Fidget Toy)
Titanium-anodized or electroplated alloy (e.g., Ti-coated Zinc or Aluminum)
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
Quartz (Common Milky Quartz)
Silicon Dioxide (SiO2)
Rough Quartz (likely Milky or Smoky Quartz)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz on Matrix
Silicon Dioxide (SiO2)
Quartz (Smoky/Milky variant)
Silicon Dioxide (SiO2)
Schist
Mica Schist
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Quartz
Silicon Dioxide (SiO₂)
Quartz (likely Rose Quartz or Milky Quartz based on color)
Quartz (SiO2 - Silicon Dioxide)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of Titanium, Iron, or Manganese
Sandstone (Pebble)
Arenite (primarily SiO2)
Gold Ore in Matrix
Native Gold (Au) in Quartz/Host Rock
Amygdaloidal Basalt
Amygdaloidal Basalt containing Zeolite and Calcite inclusions
River Pebbles (Tumbled Quartz and Basalt)
Silicon Dioxide (SiO2) for white quartz; Mafic Volcanic Rock for basalt
Chert
Chert (SiO2)
Septarian Nodule or Mud Crack Fossil
Septarian Nodule (Concretion)
Kambaba Jasper (Crocodile Jasper)
Stromatolite (Fossilized Algae within Microcrystalline Quartz), SiO2
Quartz on Sandstone
Silicon Dioxide (SiO2) in Lithic Sandstone
Eclogite
Eclogite (Omphacite + Pyrope)
Diamond in Kimberlite
Kimberlite Matrix with Carbon (Diamond)
Chevron Amethyst
Silicon Dioxide (SiO2) with iron impurities
Geode (Unbroken)
Silicon Dioxide (SiO2) usually as Microcrystalline Quartz or Chalcedony
Petrified Wood
Silicified Wood (primarily SiO2)
Quartz Geode / Druzy Quartz
Silicon Dioxide (SiO2)
Quartz Geode (Nodule)
Silicon Dioxide (SiO2)
Concretion (Sandstone)
Carbonate-cemented Sandstone Concretion
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
Olivine in Basalt (Peridotite Xenolith)
Forsterite-rich Olivine (Mg2SiO4) in Aphanitic Basalt
Gastropod Fossil (Snail Internal Mold)
Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Sandstone with Ironstone Concretion
Arenite with Hematite/Goethite nodules (Fe2O3 / FeO(OH))
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)