fergusonite

noun

fer·​gu·​son·​ite

ˈfərgəsəˌnīt

plural -s

: a brownish black mineral (Y,Er,Ce,Fe,)(Nb,Ta,Ti)O₄ consisting essentially of an oxide of yttrium, erbium, niobium, and tantalum with other metals often including uranium and isomorphous with formanite (hardness 5.5–6)

Word History

Etymology

Robert Ferguson †1865 Scottish physician + English -ite

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!