Definition of pycnite in US English:

pycnite

noun

Mineralogy
rare
  • An off-white to lemon yellow variety of topaz occurring in columnar aggregations.

Origin

Early 19th century; earliest use found in Philosophical Transactions of the Royal Society of London. From French pycnite from pycno- + -ite.

Pronunciation

pycnite

/ˈpɪknʌɪt/