Editing Mica (section)

=== Sheet mica ===
[[File:Muscovite window.jpg|thumb|Muscovite windows]]
Sheet mica is a versatile and durable material widely used in electrical and thermal insulation applications. It exhibits excellent electrical properties, heat resistance, and chemical stability.

Technical grade sheet mica is used in electrical components, electronics, atomic force microscopy and as window sheets. Other uses include diaphragms for oxygen-breathing equipment, marker dials for navigation compasses, [[Filter (optics)|optical filters]], [[pyrometer]]s, thermal regulators, stove and kerosene heater windows, radiation aperture covers for microwave ovens, and [[micathermic heater]] elements. Mica is [[birefringence|birefringent]] and is therefore commonly used to make quarter and half [[wave plate]]s. Specialized applications for sheet mica are found in aerospace components in air-, ground-, and sea-launched missile systems, [[laser]] devices, medical electronics and radar systems. Mica is mechanically stable in micrometer-thin sheets which are relatively transparent to radiation (such as [[alpha particle]]s) while being impervious to most gases. It is therefore used as a window on radiation detectors such as [[Geiger–Müller tube]]s.

In 2008, mica splittings represented the largest part of the sheet mica industry in the United States. Consumption of muscovite and phlogopite splittings was about 308 t in 2008. Muscovite splittings from India accounted for essentially all US consumption. The remainder was primarily imported from Madagascar.<ref name=usgs/>

Small squared pieces of sheet mica are also used in the traditional Japanese ''[[Kōdō]]'' ceremony to burn incense: A burning piece of coal is placed inside a cone made of white ash. The sheet of mica is placed on top, acting as a separator between the heat source and the incense, to spread the fragrance without burning it.

==== Electrical and electronic ====
[[File:Silver mica capacitors.jpg|thumb|[[Silver mica capacitor]]s]]
Sheet mica is used principally in the electronic and electrical industries. Its usefulness in these applications is derived from its unique electrical and thermal properties and its mechanical properties, which allow it to be cut, punched, stamped, and machined to close tolerances. Specifically, mica is unusual in that it is a good electrical insulator at the same time as being a good thermal conductor. The leading use of block mica is as an electrical insulator in electronic equipment. High-quality block mica is processed to line the gauge glasses of high-pressure steam boilers because of its flexibility, transparency, and resistance to heat and chemical attack. Only high-quality muscovite film mica, which is variously called India ruby mica or ruby muscovite mica, is used as a dielectric in [[capacitor]]s. The highest quality mica film is used to manufacture capacitors for [[calibration standard]]s. The next lower grade is used in [[transmitting capacitor]]s. Receiving capacitors use a slightly lower grade of high-quality muscovite.<ref name=usgs/>

Mica sheets<!--Mica heating boards? --> are used to provide structure for heating wire (such as in [[Kanthal (alloy)|Kanthal]] or [[Nichrome]]) in [[heating element]]s and can withstand up to {{convert|900|°C|°F|abbr=on}}.

Single-ended self-starting lamps are insulated with a mica disc and contained in a [[borosilicate glass]] gas discharge tube (arc tube) and a metal cap.<ref name="lamptech">{{Cite web|url=http://www.lamptech.co.uk/Documents/SO%20History%20MV-SE.htm|title=The Low Pressure Sodium Lamp}}</ref> They include the [[sodium-vapor lamp]] that is the [[gas-discharge lamp]] in street lighting.<ref name="lamptech" /><ref>{{Cite web|url=https://www.stouchlighting.com/blog/led-vs-hps-lps-high-and-low-pressure-sodium|title=Lighting Comparison: LED vs High Pressure Sodium/Low Pressure Sodium|website=www.stouchlighting.com}}</ref><ref>{{Cite web|url=https://edisontechcenter.org/SodiumLamps.html|title=The Sodium Lamp – How it works and history|website=edisontechcenter.org}}</ref>

==== Atomic force microscopy ====
Another use of mica is as a substrate in the production of ultra-flat, thin-film surfaces, e.g. gold surfaces. Although the deposited film surface is still rough due to deposition kinetics, the back side of the film at the mica-film interface is ultra-flat once the film is removed from the substrate. Freshly-cleaved mica surfaces have been used as clean imaging substrates in [[atomic force microscopy]],<ref>Eaton, P. and West, W. (2010) "Substrates for AFM", pp. 87–89 in ''Atomic Force Microscopy''. Oxford University Press. {{ISBN|978-0-19-957045-4}}.</ref> enabling for example the imaging of [[bismuth]] films,<ref>{{Cite journal | doi = 10.1116/1.585190| title = Atomically resolved images of bismuth films on mica with an atomic force microscope| journal = Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures| volume = 9| issue = 2| pages = 1333–1335| year = 1991| last1 = Weisenhorn | first1 = A. L.| bibcode = 1991JVSTB...9.1333W}}</ref> plasma [[glycoprotein]]s,<ref>{{Cite journal | doi = 10.1016/0021-9797(92)90135-9| title = Interactions of von Willebrand factor on mica studied by atomic force microscopy| journal = Journal of Colloid and Interface Science| volume = 148| pages = 261–272| year = 1992| last1 = Marchant | first1 = R. E. | last2 = Lea | first2 = A. S. | last3 = Andrade | first3 = J. D. | last4 = Bockenstedt | first4 = P. | issue = 1| bibcode = 1992JCIS..148..261M| hdl = 2027.42/30333| url = https://deepblue.lib.umich.edu/bitstream/2027.42/30333/1/0000735.pdf| hdl-access = free}}</ref> [[cell membrane|membrane bilayers]],<ref>{{Cite journal
 | pmid = 1777565
| pmc = 1260200
| year = 1991
| last1 = Singh
| first1 = S
| title = Atomic force microscopy of supported planar membrane bilayers
| journal = Biophysical Journal
| volume = 60
| issue = 6
| pages = 1401–10
| last2 = Keller
| first2 = D. J.
| doi = 10.1016/S0006-3495(91)82177-4
| bibcode = 1991BpJ....60.1401S
}}</ref> and [[DNA]] molecules.<ref>{{Cite journal
 | pmid = 1295085
| year = 1992
| last1 = Thundat
| first1 = T
| title = Atomic force microscopy of DNA on mica and chemically modified mica
| journal = Scanning Microscopy
| volume = 6
| issue = 4
| pages = 911–8
| last2 = Allison
| first2 = D. P.
| last3 = Warmack
| first3 = R. J.
| last4 = Brown
| first4 = G. M.
| last5 = Jacobson
| first5 = K. B.
| last6 = Schrick
| first6 = J. J.
| last7 = Ferrell
| first7 = T. L.
}}</ref>

==== Peepholes ====
Thin transparent sheets of mica were used for peepholes in boilers, lanterns, [[stove]]s, and [[kerosene heater]]s because they were less likely to shatter than glass when exposed to extreme temperature gradients. Such peepholes were also fitted in horse-drawn [[carriage]]s and early 20th-century cars, where they were called ''[[Isinglass#In popular culture|isinglass curtains]]''.<ref>"Isinglass curtains" are referenced in the 1943 musical ''[[Oklahoma!|Oklahoma]]''{{'s}} song "[[The Surrey with the Fringe on Top]]"</ref><ref>{{OED|isinglass, n}}</ref><ref>{{cite book
 | first = Joanne
 | last = Wilke
 | title = Eight Women, Two Model Ts and the American West
 | publisher = University of Nebraska Press
 | year = 2007
 | isbn = 978-0803260191
 | url-access = registration
 | url = https://archive.org/details/eightwomentwomod00wilk_0
 |page=28
 }}
</ref>