Chinas?

[drizzlermibs]

These groups came with my clays. Are they chinas and not clays? Pretty "meh" but just want to know your thots. The last two photos are of the same group. They seem heavier somehow and "clank" when they hit each other...Tx.

 

[cheese]

The top two pics look more like limestone maybe? Not sure if they are clay. Maybe tumbling media if they are stone?
The last group is clays with some sort of glaze or hard coating on them. I find them like that too, not sure what is on them.