What is the characteristic to break in jagged pieces?

The characteristic that leads a mineral to break in jagged pieces is known as "conchoidal fracture." This type of fracture occurs when a mineral does not have a defined cleavage plane, causing it to break irregularly and create sharp, curved surfaces. Minerals with a conchoidal fracture, such as quartz and obsidian, often exhibit a glassy luster and can produce sharp edges. This property is essential in applications like tool-making, where sharp edges are advantageous.