The common inclusion of quartz is crystallization, mainly rutile. Grass in crystal is mainly composed of tourmaline, while water tank crystal is a liquid inclusion in quartz. Blue quartz contains light blue rutile needle. Milk quartz is turbid due to fine water pores. Green quartz is composed of plate-like or fragmented chlorite, sometimes possibly green needle like actinolite. Aventurine is a kind of green or reddish brown mica flake in quartzite, also known as Yao 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. The crystal system of quartz is hexagonal crystal system.
The crystal is equiaxed, columnar, and hexagonal biconical. There are blocky, coarse-grained, bell shaped, and nodular shapes. Mohs hardness is 7, with conchoidal fracture and glassy luster. The colors of quartz stone include: colorless, white, with a touch of gray, yellow to orange yellow, purple, deep purple, pink, grayish brown, brown, black, etc. The stripes are white. The characteristics of quartz stone include brittleness, thermoelectric properties, refractive index ranging from 1.533 to 1.541, birefringence difference of 0.009, and dispersion of 0.013. Quartz has strong piezoelectric properties, and when forcefully struck and rubbed, sparks are generated, which is the method of using flint to ignite.