Physical Characters ÷hackly(锯齿状物or splintery,when it has ragged sharp points and depressions,or separates in a fiber-splinter- like manner. ÷Tenacity(韧性).-mineral is brittle when it breaks into powder; Sectile(可制成片，when small slices can be shaved off which crumble under a hammer; http://webmineral.com/help/Fracture.shtmlPhysical Characters  hackly(锯齿状的) or splintery, when it has ragged sharp points and depressions, or separates in a fiber- splinter￾like manner.  Tenacity(韧性). -- mineral is brittle when it breaks into powder;  Sectile (可制成片的), when small slices can be shaved off which crumble under a hammer; http://webmineral.com/help/Fracture.shtml