noun
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.
このコレクションは玉石混交だ。
This collection is a mixture of gems and junk.
インターネット上の情報は玉石混交だから、注意が必要だ。
Information on the internet is a mix of good and bad, so you need to be careful.