Conchoidal fracture is a type of fracture that occurs in brittle materials, such as glass or quartz, where the breakage produces smooth, curved surfaces that resemble the interior of a seashell. This fracture pattern is characteristic of materials that lack natural planes of weakness, making it important in the identification of minerals and the study of material properties.
Source Klein, C., & Hurlbut, C. S. (1999). Manual of Mineralogy. Wiley.