Noun
mixed bag; mixture of good and bad; jumble of wheat and chaff; mixture of precious gems and common rocks
Yojijukugo (four character compound)
ボスには玉石混交のグループとは言われたけれど、俺は玉かな、それとも石なのかな。The boss said this group is a real mixed bag. I wonder if he places me with the wheat or the chaff.
Also written 玉石混淆【ぎょくせきこんこう】