A student breaks a piece of quartz and notices that it splits into irregular-shaped, jagged pieces, whereas calcite, when broken, will split into smooth, flat pieces. Which of the following properties of minerals is the student observing?
A) cleavage
B) luster
C) streak
D) color

Question

Quizplus · Accepted Answer

The student is observing the property of cleavage, which describes how a mineral will break along planes of weakness in its crystal structure. Quartz does not have a well-defined cleavage, so it breaks into jagged pieces, whereas calcite has cleavage planes that cause it to break into smooth, flat pieces. Luster describes how a mineral reflects light, streak describes the color of a mineral's powder when scraped on a surface, and color is simply the color of the mineral.

A Student Breaks a Piece of Quartz and Notices That