. "1776-03-05Z"^^ . "Troost, Gerard"@en . "1850Z"^^ . "Gerard Troost (March 5, 1776 \u2013 August 14, 1850) was an American-Dutch medical doctor, naturalist, mineralogist, and founding member and first president of the Philadelphia Academy of Natural Sciences."@en . . . . "Gerard Troost"@en . . . "1776Z"^^ . "1850-08-14Z"^^ . "American mineralogist" .