DICT.TW Dictionary Taiwan

 ob·sid·i·an /əbˈsɪdiən/
 黑曜石,十勝石

 ob·sid·i·an n.  Min. A kind of glass produced by volcanoes.  It is usually of a black color, and opaque, except in thin splinters.
 Note: ☞ In a thin section it often exhibits a fluidal structure, marked by the arrangement of microlites in the lines of the flow of the molten mass.
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 obsidian
      n : acid or granitic glass; usually dark, but transparent in
          thin pieces