Fracture Minerals having chemical bonds that are equally, or nearly equally, strong in all directions exhibit a property called fracture. When minerals fracture, most produce uneven surfaces and are described as exhibiting irregular fracture. However, some minerals, such as quartz, break into smooth, curved surfaces resembling broken glass. Such breaks are called conchoidal fractures (Figure 2.18). Still other minerals exhibit fractures that produce splinters or fibers that are referred to as splintery and fibrous fracture, respectively.