gems and stones; wheat and chaff; good and bad
Often used in the set phrase 玉石混交 (or 玉石混淆) meaning 'a mixture of the good and the bad' or 'wheat and tares'. As a standalone noun it refers to gems and ordinary stones, metaphorically the valuable and the worthless.
This collection is a mixture of gems and junk.
Information on the internet is a mix of good and bad, so you need to be careful.
topaz
From Chinese 玉石 (yùshí), literally 'jade and stone', used metaphorically for good and bad things mixed together.