Literature Review

Quartz has been extensively studied due to its remarkable properties and broad utility.

1.Natural Quartz vs. Synthetic Quartz

石英矿图片_石英矿素材_石英矿高清图片_摄图网图片下载 Fig.4 Natural Quartz[22]

神光光学合成石英锭料_报价-神光光学集团有限公司 Fig.5 Synthetic Quartz[23]

Natural quartz is cost-effective but may contain impurities, while synthetic quartz (grown via hydrothermal methods) offers superior purity for precision applications. The main component of quartz is SiO2. In addition, the content of high-purity quartz is greater than 99.9%, and that of ultra-high-purity quartz is greater than 99.999%[1]. Subsequent advancements in purification and crystal growth techniques enabled the production of synthetic quartz with ultra-high purity, essential for semiconductor and optical applications. More information about properties can be found on the processing.

2.Crystallography and Physical Properties

Fig.6 Phase transition of quartz[1]

Quartz refers to low-temperature quartz, namely α -quartz, which is the most widely distributed quartz mineral. Broadly speaking, quartz also includes high-temperature quartz (β- quartz), tridymite, cristobalite, coesite, etc. Quartz crystals are oxide minerals with the trigonal or hexagonal system, whose cell parameters are: a = 4.916 Å, b = 4.916 Å, c = 5.405 Å. The Si-O bond angle in α-quartz is 144° and the bond length is 0.16101~0.16145 nm.[1]

Pure quartz is colorless and transparent but impurities and inclusions can reduce its transparency and change its color. Quartz has a vitreous luster, a hardness of 7, no cleavage, a density of 2.65 g/cm ³, a melting point of approximately 1750℃. As a standard crystal, quartz is remarkably anisotropic in terms of chemical, thermal, and mechanical properties. More information about properties can be found on the property profile.

3.Piezoelectricity

Fig.7 Piezoelectricity Drawing[24]

The discovery of piezoelectricity in quartz by the Curie brothers in 1880 enabled quartz’s use in oscillators and sensors, making it crucial for oscillators, sensors, and timing devices.

The quartz piezoelectricity is based on the piezoelectric effect, which states that when mechanical stress or forces are applied to a quartz crystal, it produces electrical charges on the crystal surface[2]. More information about properties can be found on the property profile.

4.Optical Properties

Fig.8 Colorful Quartz Crystal[25]

Quartz is widely used in optical fiber transmission and photovoltaic fields due to its high refractive index. Meanwhile, quartz has the property of light transmission to make silicon glass, but the presence of impurities such as Fe and Al in quartz reduces its light transmission, affecting the performance of silicon glass and silicon optical fibers.

Studies on fused quartz’s UV transparency have driven advancements in lithography and astronomy. More information about properties can be found on the property profile.

5.Thermal and Chemical Stability

Fig.9 Quartz Crucible[26]

Quartz exhibits low thermal expansion and high resistance to corrosive environments, making it ideal for high-temperature and harsh-condition applications in refractory materials, mechanical casting, chemical engineering and other fields. A typical example is silica crucible. More information about properties can be found on the property profile.

2.Literature Review

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