nugget

n 1 lump of (esp valuable) metal, eg gold, found in the earth （尤指贵重的）金属块（如天然金块）. 2 (fig 比喻) small thing that is regarded as valuable （有价值的）小东西: a book full of nuggets of useful information 有很多有用的零碎资料的书.

nub, nubile, nuclear, nuclear disarmament, nuclear energy (also nuclear power), nuclear family, nuclear war, nuclear winter, nuclear-free, nucleate, nucleic acid, nucleolus, nucleus, nude, nudge, nudism, nudist, nudist camp (also nudist colony), nudity, nugatory, nuisance, null, nullification, nullify, nullity, numb, number, number one, numberless, numbly, numbness, numeracy, numeral, numerate, numeration, numerator, numerical, numerically, numerous, numinous,