Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Category
Browse mineral like (natural glass) specimens identified by the Rock Identifier community.
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Carnelian
Carnelian (Silicon Dioxide - SiO2 with iron oxide impurities)
Asphalt (Bituminous Slate/Sandstone)
Asphaltum / Bituminous Rock
Diamond
Diamond (C)
Howlite (Tumbled)
Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)
Apache Tear
Hydrated Obsidian (Natural Volcanic Glass)
Black Tourmaline (Schorl)
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
Shale
Fissile Mudstone (primarily composed of clay minerals and quartz)
Smoky Quartz with Siderite and Pyrite
Silicon Dioxide (SiO2) with Ferrous Carbonate (FeCO3) and Iron Sulfide (FeS2)
Blue Quartzite (Blue Aventurine / Dumortierite Quartz)
Quartzite with inclusions (SiO2 with AlAl4BSi3O18)
Rose Quartz
Silicon Dioxide (SiO2)
Fluorite (Rainbow Fluorite Point)
Calcium Fluoride (CaF2)
Basalt with Scoria/Vesicular Texture
Vesicular Basalt (Iron-rich/Oxidized)
Mica Schist
Mica Schist (Complex Silicate Rock)
Diamond
Diamond (pure carbon; C)
Sandstone
Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)
Granite
Granite (phaneritic intrusive felsic igneous rock)
Pink Granite
Granite (Phaneritic Felsic Igneous Rock)
Cobalt Glass Slug (Man-made Glass)
Amorphous Silica with Cobalt Oxide (SiO2 + CoO)
Obsidian
Volcanic glass (SiO2 + impurities)
Limonite (Yellow Ochre)
Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)
Red Sandstone
Clastic sedimentary rock (primarily SiO2 with Fe2O3)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with impurities of iron)
Obsidian
Volcanic Glass (SiO2 + minor impurities)
Artisanal Glass Beads (Simulated Goldstone or Aventurine Glass)
Silicon Dioxide (SiO2) with metallic inclusions
Granite
Granite (Felsic Plutonic Rock)
Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
Quartz (Crystal Fragment)
Silicon Dioxide (SiO2)
Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
Granite
Intrusive Felsic Igneous Rock
Sodium Polyacrylate (Superabsorbent Polymer)
Sodium Polyacrylate [-CH2-CH(COONa)-]n
Obsidian
Volcanic glass (Mainly SiO2)
Dyed Pumice
Vesicular Rhyolite (Artificial Coloration Addition)
Magnetic Hematite
Magnetized Hematite (an iron oxide mineral, Fe2O3, that has undergone magnetization)
Satin Spar (Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Natural Pearl
Calcium carbonate (primarily Aragonite and Conchiolin), CaCO3
Ruby
Corundum (Al2O3 with Chromium impurities)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Obsidian
Obsidian (Volcanic Glass, SiO2)
Quartz (likely tumbled or naturally water-worn)
Quartz (SiO₂ - Silicon Dioxide)
Granite
Granite (Mainly Quartz, Feldspar, and Mica)
Jewelry Chain with Blue and Clear Gemstones (Likely Cubic Zirconia)
Cubic Zirconia (ZrO₂), Silver or White Gold/Platinum Alloy