I found this rock on a beach in the Northwest of England. It looks like turquoise but clearly that is unlikely in this location. It is fairly soft to the point that I was able to cut it quite easily with a dremel and sand it with a power sander. It gave up a blue chalky dust. Any ideas what it is?
This is the other side
Turquoise is usually darker, and indeed that is an unlikely location for turquoise. What type of rock matrix is there in that region? Another option is chalk colored light blue from marine sediments...
The area where I found it is all sand, a huge beach with sand dunes going inland for a half mile. There are generally no surface rocks visible, just sand which is why this stood out. I guessed from the rounded sea worn appearance that it has been washed up here after rolling around the sea for quite some time.
Looks like sandstone covered by some mineral like calcium or chalk like the last poster said.