German Slate from Marc (200 x 60 x 18mm)

Size: 200 x 60 x 18mm weight:  634gr.
Density: XXXgr./cm³ /
Estimated grit size:  medium fine – fine > 6K- 9K
Usage: only use water, no oil or grease!
Color: dark grey with darker spots, contains Pyrite inclusions
Gifted from: Marc