Example of a conchoidal (shell-like) fracture in a piece of obsidian

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.

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.