|Halpern, Alvin. Schaum's Outlines Beginning Physics II. New York: McGraw-Hill Companies, Inc., 1998: 141.||"Values of Resistivity of Materials
Material Resistivity (Ωm)
|7.5 × 1017 Ωm|
|Bleaney, B.I. & B. Bleaney. Electricity and Magnetism 3rd Edition. Great Britain: Oxford University Press, 1976: 63.||"Specific Substance Resistance at 273 K (Ωm)
Fused Quartz >5 x1016"
|> 5 × 1016 Ωm|
|Ward, Roger W. The Constants of Alpha Quartz. IEEE Ultrasonics, Ferroelectrics and Frequency Control Society, September 1992.||
|>6 × 105–2 × 1014 Ωm|
|Material Information Quartz-Fused SiO2. Good Fellow.||"Volume Resistivity @25C (Ohm cm) 1018"||1 × 1017 Ωm|
The most common form of crystal on earth is quartz, which can be found in nearly every geological environment. It is a crystalline form of silicon dioxide (SiO2) also known as silica. Quartz crystals vary in color with impurities and include the rose quartz, smoky quartz, amethyst, and citrine.
In every day application quartz crystals are used in optical lenses, lasers and as electrical components. Quartz crystals act as insulators with their high electrical resistivity which is said to reach anywhere from 105 to 1018 Ωm. In fact, quartz crystals are able to act as excellent insulators even at elevated temperature. Clear fused quartz is said to oppose electric current better than opaque or translucent types of quartz and rightly have higher values of electrical resistivity.
Based on the quartz crystals' insulating properties it is used as filler material for resins in electronic circuits. Being made of silicon it is also an intrinsic semiconductor. Microprocessor chips, transistors and anything that uses radio waves or is computerized will depend on semiconductors and, thus, may depend on quartz. Quartz is also considered a piezoelectric material and as such can have induced electric fields established across its surface after having external forces applied to it. Changing the external force exerted on a piezoelectric material will change the direction of the induced electromotive force produced by the electric field. As piezoelectric material, quartz is used in transducers, ultrasonic generators and echolocation devices.
Some people believe that the various quartz crystals have mystical powers that can aid humans although no scientific evidence has proven these beliefs. For example, it is said that an amethyst can be used to channel ones thoughts and a rose quartz can be held on oneself to attract love. They're also believed to have the ability to heal a few of the chakra points in the human body, which are "spinning energy centers"found in seven locations of the body according to the belief of basic crystal healing. By placing a certain crystal on the chakra point in the body people can supposedly cleanse themselves of negative energy and enjoy better health and a sense of well-being. In this system, amethyst would be used for the "crown"and "forehead"chakras of the body while the rose quartz would be used for the "heart"chakra.
Jennifer Schanke -- 2004