Marble.
Texture doesn't look like belorechit.
Too little pyrite.
Belorechit has another type of crack surf

x350

more pics
https://yadi.sk/d/MBr8ZTLwtkYco/Russ...82%D1%8B%D0%B9
https://yadi.sk/d/MBr8ZTLwtkYco/Russ...87%D0%B8%D1%82