I picked up this stone from the seashore today for one of my bonsai projects. In the photo it looks like it’s blue on the lower half and black on the upper half but that’s just the light from the camera. It is black on both sides. I don’t know what kind of stone it is and worse I don’t know what the white deposits are. One side is completely covered in it. My guess is it’s “kalk”. Must I try to chip it all away or can I soak it in something to make it easier? Is it a granite stone maybe?
