Webster's Revised Unabridged Dictionary · 1913

Nugget

Nugget , noun

[Earlier niggot, prob. for nigot, an ingot. See Ingot.]

1.
A lump; a mass, esp. a native lump of a precious metal; as, a nugget of gold.
2.
Something of value, usually found among many other less valuable things; -- often used figuratively; as, a nugget of useful information in a sea of data.