(1) Brittle.

(2) It has thermoelectric properties.

(3) Refractive index 1.533~1.541, birefringence difference 0.009, dispersion 0.013.

(4) Quartz has a strong piezoelectric property, which generates sparks when forcefully struck and rubbed, which is the method of igniting flint.

(5) The common inclusions in quartz are: hair crystal - mainly Rutile. Grass into crystal - mainly Tourmaline; There are liquid inclusions in water bile crystal quartz; Turquoise - containing Baby blue Rutile needle; Milk quartz - turbidity caused by fine water pores; Green quartz - composed of plate-like or fragmented Chlorite group, sometimes green needle like Actinolite; Aventurine - quartzite contains green or reddish brown mica flakes inside, also known as corundum quartz, commonly known as Dongling stone. The common smoky black to dark brown smoky crystals are mainly due to the high content of radioactive uranium and thorium elements in these rocks.