Why Worth Its Weight in Gold?

: very useful, valuable, or important Good teachers are worth their weight in gold.

Where did worth its weight in gold come from?

worth one's weight in gold

Very valuable, as in John's been extremely helpful; he's worth his weight in gold, or That tractor's been worth its weight in gold. This metaphoric term dates from Roman times and appeared in English by the early 1300s.

Which trade item is worth its weight in gold?

Indeed, salt was such a precious commodity that it was quite literally worth its weight in gold in some parts of West Africa.