Samuel Lewis Penfield (January 16, 1856 – August 12, 1906) was an American analytic chemist, mineralogist, and crystallographer who first obtained the chemical structures of more than two dozen naturally occurring minerals.
Except for brief periods abroad, in Germany (where he trained in crystallography), his entire subsequent career was to be at Yale.
In early work, He analyzed the then-new so-called Branchville phosphates, fairfieldite and fillowite, as well as samples of chabazite and rhodocrosite from the same locality.
[3] Penfield's scientific work may be summarized as comprising mineralogical investigations of great abundance, variety, accuracy, and importance.
[1][2] Penfield remained unmarried for twenty years after his graduation from college and lived in an apartment in South Sheffield Hall.