what things are made out of metamorphic rocks?
['This is an incomplete list:', 'Roof tiles (Slate)', 'Building facades, tile, and counters (marble, gneiss, quartzite, etc.)', 'Whetstones (fine slate)', 'Electrical insulator (a variety of rocks, including slate)', 'Thermal insulation (mineral asbestos and less problematic asbestoform minerals)', 'Billiard Tables (slate)']