Sorcerer's sand

From Sword of Truth Wiki

Sorcerer's sand is sand made from the crystallized bones of older wizards. Spells drawn in white sorcerer's sand must be drawn perfectly, or the consequences could be deadly.

Black sorcerer's sand is the counterpart to white sorcerer's sand, black sorcerer's sand is extremely rare. A single grain of black sorcerer's sand can negate the effects of a spell drawn in white sorcerer's sand. Like white sorcerer's sand, the black version is also the product of the crystallized bones of wizards. Even a tiny amount of black sorcerer's sand is extremely valuable, nearly priceless.

White and Black sand are created based on the way the wizard gives up his life or makes the Wizards life fire. Black to save himself, White to save others.