Black Obsidian
Amorphous volcanic glass (SiO2 + impurities)
Category
Browse antropogenic (man made) specimens identified by the Rock Identifier community.
Black Obsidian
Amorphous volcanic glass (SiO2 + impurities)
Conglomerate
Conglomerate Rock (Paraconglomerate)
Sandstone Concretion
Clastic sedimentary rock (primarily Quartz SiO2)
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Slag
Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)
Titanium Amethyst Geode
Silicon Dioxide (SiO2) with Titanium/Metal Vapor Deposition Layer
Metal Alloy (Likely Pewter or Sterling Silver)
Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).
Slag (Industrial Glass/Glassy Rock)
Anthropogenic Vitreous Material
Sea Glass (White/Clear)
Amorphous Silica (Alkali-Lime-Silica Glass), SiO2 + Na2O + CaO
Aura Quartz
Titanium/Titanium-Gold treated Silicon Dioxide (SiO2)
Red Slag Glass
Amorphous Silica (Industrial byproduct with metallic oxide dopants)
Opalite
Synthetic Opalised Glass
Carborundum (Silicon Carbide)
Silicon Carbide (SiC)
Blue Goldstone
Man-made glass with suspended copper, cobalt, or manganese particles
Goldstone
Aventurine Glass (Man-made glass with copper inclusions)
Granite with Cupules / Bedrock Mortars
Granite (felsic intrusive plutonic rock)
Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)
Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)
Green Glass (often marketed as 'Obsidian' or 'Green Quartz')
Amorphous Silica (SiO2) with copper or chromium additives
Blue Crackle Quartz (Dyed Quarzite)
Silicon Dioxide (SiO2) with artificial dye
Dyed Blue Agate (Dragon Vein Agate)
Silicon Dioxide (SiO2) with artificial cobalt/organic dyes
Diamond
Native Carbon (C)
Dyed Aura Quartz
Silicon Dioxide (SiO2) with metallic coating
Goldstone (Red)
Aventurine Glass (SiO2 + Cu)
Ferro-slag (Leland Blue/Slag Glass)
Anthropogenic Vitreous Silica (Industrial Slag)
Blue-green cabochon, likely chalcedony or treated glass imitation
Cryptocrystalline quartz (chalcedony/possibly chrysoprase); identification uncertain from image
Blue Obsidian
Volcanic Glass (SiO2 with inclusions)
Green glass sphere/marble
Soda-lime glass (primarily SiO2, Na2O, CaO)
Blue Obsidian (Cullet Glass)
Silicon Dioxide (Amorphous Glass)
Opalite crescent pendant
Opalite (man-made opalescent glass; not a natural mineral)
Sea Glass
Man-made vitreous material (silica-based glass)
Sea Glass
Man-made silicate glass (Amorphous silicon dioxide)
Goldstone (Brown/Gold)
Aventurine Glass (Man-made glass with Copper inclusions)
Porcelain Tile (Sandstone-look)
Man-made Ceramic (resembling Quartz-rich Sandstone)
Hematite
Iron(III) oxide (Fe2O3)
Opalite (Man-made Glass)
Fused glass (typically made of dolomite and metal opacifiers)
Cobalt Glass Slug (Cullet)
Man-made Silicate Glass with Cobalt Oxide (CoO)
Cullet (Slag Glass)
Amorphous Silica (Industrial byproduct)
Opalite
Synthetic Opalised Glass
Carborundum (Silicon Carbide)
Silicon Carbide (SiC) / Moissanite (natural form)
Carborundum
Silicon Carbide (SiC)
Opalite
Synthetic glass (SiO2 + metal additions)
Metallic sulfide mineral fragment, likely galena
Galena (lead sulfide, PbS), tentative identification