Trip·o·li /ˈtrɪpəli/
  矽藻土
  Trip·o·li n. Min. An earthy substance originally brought from Tripoli, used in polishing stones and metals. It consists almost wholly of the siliceous shells of diatoms.
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  tripoli
       n 1: a weathered and decomposed siliceous limestone; in powdered
            form it is used in polishing [syn: rottenstone]
       2: the capital and chief port and largest city of Libya; in
          northwestern Libya on the Mediterranean Sea; founded by
          the Phoenicians in the 7th century BC [syn: Tarabulus
          Al-Gharb, capital of Libya]
       3: a port city and commerical center in northwestern Lebanon on
          the Mediterranean Sea [syn: Tarabulus Ash-Sham, Trablous]