Diamond
Carbon (C)
Category
Browse mineraloid (man made origin) specimens identified by the Rock Identifier community.
Diamond
Carbon (C)
Mahogany Obsidian
Volcanic Glass with Hematite (SiO2 + Fe2O3)
Black Obsidian
Volcanic Glass (SiO2 + impurities like Fe3O4)
Opal
Hydrated silica (SiO2 "NH2O)
Snowflake Obsidian
Spherulitic Obsidian (Volcanic Glass with Cristobalite inclusions)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Snowflake Obsidian
Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions
Obsidian
Volcanic Glass (SiO2)
Amber
Amber (C10H16O)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Agate
Chalcedony (SiO2)
Red Coral
Corallium rubrum
Obsidian
Amorphous volcanic glass (SiO2)
Amber
Fossilized Tree Resin
Rough Quartz (Milky / Clear Quartz)
Silicon Dioxide (SiO2)
Quartz (Milky / Clear Quartz Fragment)
Silicon Dioxide (SiO2)
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals: (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
Emerald
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
Fluorite in Matrix
Calcium Fluoride (CaF2) with Quartz/Calcite matrix
Green Fluorite (Botryoidal/Massive)
Calcium Fluoride (CaF2)
Emerald In Matrix
Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium
Granodiorite
Granodiorite
Polished blue-green glassy slag or coated mineral fragment
Most likely man-made colored glass/slag; exact composition cannot be determined visually
Blue goldstone beads
Man-made aventurine glass (silica glass with metallic copper inclusions), not natural lapis lazuli
Black Pearl (Tahitian Pearl)
Aragonite / Calcite (CaCO3) with Conchiolin
Brown quartz-rich stone, possibly smoky quartz or quartzite
Quartz (SiO₂), potentially in a quartzite or silica-rich matrix
Green-and-white quartz-rich rock, likely chrysoprase or serpentine-bearing stone
Uncertain; possible chrysoprase (microcrystalline quartz, SiO₂) or serpentinite (magnesium silicate minerals)
Piddock-bored Mudstone
Lutite (Siltstone or Mudstone) with Pholad borings
Fossiliferous Limestone (Coral Rag)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Fluorite (Fluorescent)
Calcium Fluoride (CaF2)
Mixed Mineral Collection
Multi-mineral Assemblage (Quartz, Jasper, Obsidian, Pyrite, etc.)
Diamond (in a jewelry setting)
Diamond (Carbon, C)
Obsidian
Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Limonite (Iron Stone/Ocher)
Limonite (FeO(OH)·nH2O)
Obsidian
Obsidian (Volcanic Glass)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions (70–75% SiO2)
Black Obsidian
Obsidian (Amorphous Silicon Dioxide)
Snowflake Obsidian
Volcanic Glass with Cristobalite Inclusions