I have around 120 sq foot of Granite counter tops (Ubatuba) And i use it as a contraceptive. Just rest my balls on the surface for 20 minutes and all the sperm dies.
Its a bit like the old wives tale in the UK when people placed as watch with glowing hand next to their balls because the watch hands used to be covered with a radio active material to make them glow at night . Supposedly the radiation killed sperm ( most likely mutated it ?? )
