A break or chip, caused by stress, that is in any direction other than parallel to the planes of atoms in a crystalline mineral. The most common type of fracture appears shell-like and is called conchoidal.

Example of a Conchoidal (Shell-Like) Fracture in a Piece of Obsidian.


  1. Conchoidal Fracture
    • Has a curved shell-like appearance. This is the most commonly occurring type of fracture.
  2. Even Fracture
    • These are smooth in appearance but without the single plane regularity of cleavage. This can be seen in some types of quartz.
  3. Uneven Fracture
    • Similar to the edge of broken pottery. This can be found in most all minerals and rocks.
  4. Splintery Fracture
    • This is usually observed in nephrite and hematite. Sometimes this is referred to as fibrous.