Why doesn't quartz have any cleavages, only fractures?
A) It is made of pure silicon which is very strong.
B) All oxygens are shared between strongly bonded silicons in a 3- D framework.
C) It has strong helical chains in three perpendicular directions.
D) All of the metallic cations form strong webs between the silicate chains.

Question

Quizplus · Accepted Answer

Quartz lacks cleavage because its structure consists of a continuous 3-D framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. This strong, covalent bonding throughout the crystal structure does not allow for planes of weakness that would result in cleavage.

Why Doesn't Quartz Have Any Cleavages, Only Fractures