fissility

/fɪˈsɪləti/
noun
  1. The quality of being easily split or divided along natural planes, especially in rocks or minerals.
    • The rock's fissility allowed it to be split into flat slabs for roofing.
    • The fissility of shale makes it easy to break into thin layers.
    • Geologists study the fissility of slate to understand how it was formed.