Why is Quartz hard?

Quartz has a crystal structure composed of one silicon atom surrounded by four Oxygen atoms ( SiO4) . This structure is similar to a pyramid (a tetrahedron with 4 corners, four faces and six straight edges). read more

Quartz has a crystal structure composed of one silicon atom surrounded by four Oxygen atoms ( SiO4) . This structure is similar to a pyramid (a tetrahedron with 4 corners, four faces and six straight edges). Each Oxygen atom occurring at the corner of one tetrahedron is bonded to its neighboring tetrahedron. read more

Strength: Quartz is a very hard mineral and able to withstand high pressures produced during the hydraulic fractur-. Quartz: Identification, Varieties, and Meaning - Geology - Quartz is essential to the land as we know it. read more

On the Knoop scale of hardness quartz is 820 times as hard as talc, the softest common mineral. FWIW diamond ranks at 7000. Different colors of quartz occur because of various other elements that are within the mineral. Amethyst being a common example. read more