ba·salt /bəˈsɔlt, ˈbeˌ/
 玄武岩


 Ba·salt n.
 1. Geol. A rock of igneous origin, consisting of augite and triclinic feldspar, with grains of magnetic or titanic iron, and also bottle-green particles of olivine frequently disseminated.
 Note: ☞ It is usually of a greenish black color, or of some dull brown shade, or black. It constitutes immense beds in some regions, and also occurs in veins or dikes cutting through other rocks. It has often a prismatic structure as at the Giant's Causeway, in Ireland, where the columns are as regular as if the work of art. It is a very tough and heavy rock, and is one of the best materials for macadamizing roads.
 2. An imitation, in pottery, of natural basalt; a kind of black porcelain.

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 basalt
      n : the commonest type of solidified lava; a dense dark gray
          fine-grained igneous rock composed chiefly of
          calcium-rich plagioclase feldspar and pyroxene