nugget
Concise Oxford English Dictionary © 2008 Oxford University Press:
nugget/ˈnʌɡɪt/
▶noun
- 1 a small lump of gold or other precious metal found ready-formed in the earth.
- 2 a small but valuable fact.
– derivatives
nuggety adjective (chiefly Austral./NZ).
nuggety adjective (chiefly Austral./NZ).
– origin C19: appar. from dial. nug ‘lump’, of unknown origin.
'nugget' also found in these Oxford entries:

