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A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under extreme pressure. Opal is another mineraloid because of its non-crystal nature. Pearl, considered by some to be a mineral because of the presence of calcium carbonate crystals within its structure, would be better considered a mineraloid because the crystals are bonded by an organic material, and there is no definite proportion of the components.

Common mineraloids[]

  • Allophane, solid (IMA/CNMNC valid mineral name)
  • Amber, non-crystalline structure, organic
  • Anthracite or hard coal
  • Bituminous coal
  • Chlorophaeite
  • Chrysocolla, solid (IMA/CNMNC valid mineral name)
  • Deweylite, a mixture of serpentine and talc or stevensite
  • Diatomite
  • Ebonite, vulcanized natural or synthetic rubber (organic); lacks a crystalline structure
  • Fulgurite, a variety of the mineraloid lechatelierite
  • Gallium, as liquid
  • Jet, non-crystalline nature, organic (very compact coal)
  • Lechatelierite, nearly pure silica glass, solid (IMA/CNMNC valid mineral name)
  • Leonardite
  • Libyan desert glass
  • Lignite or brown coal
  • Limonite, a mixture of oxides and hydroxides of iron
  • Mercury, liquid (IMA/CNMNC valid mineral name)
  • Moldavite
  • Mookaite/Radiolarite
  • Obsidian, volcanic glass – non-crystalline structure, a silica rich glass
  • Opal, non-crystalline hydrated silica silicon dioxide, solid (IMA/CNMNC valid mineral name)
  • Ozokerite, a black waxy hydrocarbon mixture
  • Palagonite
  • Pearl, organically produced carbonate
  • Pele's Hair
  • Petroleum, liquid, organic
  • Psilomelane
  • Pumice
  • Pyrobitumen, amorphous fossilized petroleum (noncrystalline, organic)
  • Shungite, black, lustrous, more than 98 weight percent of carbon
  • Sideromelane, volcanic glass – non-crystalline, an iron rich, silica poor glass
  • Tektite, meteoritic silica rich glass
  • Water, e. g. as inclusions in other crystals, liquid
  • Zietrisikite, a mineral hydrocarbon wax

See also[]

  • List of minerals - Mineraloids are listed after minerals in each alphabetically sorted section.
  • Nonmineral

References[]

  • Mineraloids are not true minerals


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