A crysknife was a knife whose blade was made from the tooth of a dead sandworm of Arrakis. It was the weapon of choice for the Fremen, the natives of Arrakis. It was a curved and double-edged blade (double-edged like a kindjal), some 20 centimeters long, milky white in color and iridescent, and had a black handle with deep finger ridges separated from the blade by a slim round ring instead of a shearing-guard. The tip of a crysknife was also commonly poisoned, with an unnamed poison residing where the nerve of the tooth used to be. This poison is quick-acting and powerful as shown with the killing of the Laza tigers by Leto II and Ghanima. Same as movie props, full scale 1:1