fissile

a. [ L. fissilis, fr. fissus, p. p. of findere to split. See Fissure. ] 1. Capable of being split, cleft, or divided in the direction of the grain, like wood, or along natural planes of cleavage, like crystals. [ 1913 Webster ]

This crystal is a pellucid, fissile stone. Sir I. Newton. [ 1913 Webster ]

2. Fissionable. [ PJC ]