Types of Quartz – A Thomas Buying Guide

There are many types of quartz. Consider this.

According to Thomas Net:

Quartz is an abundant mineral found in the earth’s surface which is formed from silicon dioxide or SiO2. Quartz is prized as a gemstone because of the many varieties of the mineral which exhibit different colors and the fact that it has hardness and durability, allowing it to polish well. Some familiar types of quartz gemstones include:

  • Agate
  • Ametrine
  • Amethyst
  • Aventurine
  • Bloodstone
  • Carnelian
  • Citrine
  • Chalcedony
  • Prasiolite
  • Rose quartz
  • Cat’s eye
  • Hawk’s eye
  • Tiger’s eye
  • Smokey quartz

Two principal forms of quartz include Macrocrystalline quartz and Microcrystalline (also called Cryptocrystalline) quartz. The distinction in these forms lies in the size of the crystal formations, with Macrocrystalline crystals being visible to the naked eye and Cryptocrystalline requiring the aid of a microscope to view.

Types of Quartz used in Industrial Applications

Quartz possesses many useful physical properties that render it a suitable material for creating a range of products that have important industrial applications. Below we provide examples of these quartz products and their use, which include:

  • Quartz Crystal Oscillators
  • Quartz Labware
  • Quartz Insulation
  • Quartz Lamps & Heaters
  • Optical Quartz Products

Quartz Crystal Oscillators

Quartz crystals have piezoelectric properties, which enables them to function as a stable resonator and therefore is valuable in electronics applications to be used as a quartz crystal oscillator. When an electric field is applied to a quartz crystal, the crystal mechanically distorts, which is a property called inverse piezoelectricity or electrostriction. As the voltage is removed, the crystal returns to its prior shape and in the process generates an electric field. This property allows quartz crystal oscillators to function across a broad frequency band from kilohertz up through Gigahertz. Consumer devices such as quartz watches and clocks make use of these oscillators, and in industrial applications, test and measurement devices, such as oscilloscopes, frequency generators, and counters contain quartz crystal oscillators as well.

Quartz Labware

Quartz has a hardness of 7 on the Mohs scale, where diamond is a 10 and talc, a very soft mineral, is a 1. It is also non-reactive chemically to most substances and is impermeable to most gases, properties which make it suitable for use in laboratory glassware. Fused quartz, as well as quartz sand (also called silica quartz), can be used to create transparent vessels used as laboratory equipment, including quartz tubing, quartz rods, quartz flasks, and quartz beakers, to name a few common examples. The generic term for fabricated quartz products such as these is quartzware.

Other standard fused silica or quartz items include quartz condensing tubes, quartz plates, quartz discs, and quartz frits, which are porous filters that are created by bonding together grains of quartz glass. Frits are available in different levels of porosity, measured by the nominal pore size in microns.

Quartz Insulation

Quartz has a high thermal resistance and is non-flammable, making it suitable for use as an insulator material. Quartz fibers are fabricated and formed into a wool that can be used to create a variety of insulation products, similar to fiberglass. The same wool material is also used in the filtration of high-temperature gases and is available in different grades from coarse to ultra-fine.

Quartz Lamps & Heaters

Quartz lamps also referred to as quartz heat lamps, are typically fabricated using tungsten filaments encased and sealed in quartz tubes. Quartz remains stable at the high temperatures generated by the lamp and is also transparent to radiation in the infrared part of the spectrum, thus making it an ideal material for use in this application. Lamp elements are also referred to as quartz halogen lamps.

Quartz heaters also make use of quartz heating elements and operate on the same principle, using infrared radiation as the heat transfer mechanism, rather than heating the air as with convection heaters. Infrared heating is generally classified by the wavelength, known as short wave infrared, medium wave infrared, and long wave infrared. These types of heaters are commonly used in settings such as outdoor patios, where convection heat is not practical as there is no insulation available to trap the warmed air.

Optical Quartz Products

With a refractive index tightly clustered around 1.54 – 1.55 in all forms, quartz it is also desirable for use in optical applications. Quartz may be fabricated into quartz windows or quartz lenses for use in focusing or collimation in laser and optical products. An important property of quartz is that it possesses a low coefficient of dispersion, which is a measure of how the index of refraction varies as a function of the wavelength when passing through a transparent medium. In lenses and other optical components, minimizing dispersion is desirable.

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