Definition of penfieldite in US English:

penfieldite

noun

Mineralogy
  • A rare mineral of the hexagonal system which consists of a basic lead chloride, Pb₂Cl₃OH, and typically occurs as tiny prisms, colourless when pure.

Origin

Late 19th century. From the name of Samuel L. Penfield, U.S. mineralogist + -ite.

Pronunciation

penfieldite

/ˈpɛnfiːldʌɪt/