What is "wood tin"

Cassiterite \Cas*sit"er*ite\, n. [Gr. ? tin.] (Min.) Native tin dioxide; tin stone; a mineral occurring in tetragonal crystals of reddish brown color, and brilliant adamantine luster; also massive, sometimes in compact forms with concentric fibrous structure resembling wood ( wood tin), also in rolled fragments or pebbly ( Stream tin). It is the chief source of metallic tin. See Black tin, under Black.

n. cassiterite