blue vitriol
blue copperas
blue stone
chalcanthite

"Is the stone in these walls really blue, or does it just look that way?"

The third was a simple metal band with red, white, and blue stones.

I think the blue stones look a little cold next to the diamond.

I looked at the blue stones lying in their hands.

He wore a single ring of some deep blue stone.

On the ridge was a house built of blue stone.

Has a blue stone in his head from drinking the moon spring water.

This place was famous for a kind of deep blue stone.

"And that's why you asked if the man was wearing a blue stone."

Still shivering, she returned to the living room to look for the blue stone.