Minerals like quartz that break into pieces with jagged edges exhibit a property called conchoidal fracture. This means they break in a curved, shell-like manner, leaving smooth, curved surfaces with sharp, jagged edges.

Here are some other minerals that also exhibit conchoidal fracture:

* Obsidian: A volcanic glass that often breaks into very sharp pieces.

* Flint: A hard, dense form of silica, used historically for tools and weapons.

* Chalcedony: A cryptocrystalline silica mineral, often used in jewelry.

* Opal: A hydrated amorphous silica mineral, known for its iridescent play of color.

Why do these minerals break this way?

Conchoidal fracture is characteristic of minerals with strong, uniform chemical bonds. This means the atoms within the mineral are tightly bound together, resulting in a consistent structure throughout. When these minerals are subjected to stress, they break along curved paths that minimize the amount of energy required for the fracture.

The smooth, curved surfaces are formed by the propagation of the fracture along these paths, while the jagged edges are created where the fracture meets a boundary or imperfection in the mineral structure.