Chaoite or white carbon is a mineral

Mineral

A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

 described as an allotrope of carbon

Carbon

Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 whose existence is disputed. It was discovered in shock-fused graphite gneiss

Gneiss

Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks.-Etymology:...

 from the Ries

Ries

Ries is the German word for a unit of paper ream, derived from the Arabic word rizma.The term can refer to:-Geography:* Nördlinger Ries, a large circular depression in western Bavaria, Germany....

 crater in Bavaria. It has been described as slightly harder than graphite, with a reflection colour of grey to white. From its electron diffraction

Electron diffraction

Electron diffraction refers to the wave nature of electrons. However, from a technical or practical point of view, it may be regarded as a technique used to study matter by firing electrons at a sample and observing the resulting interference pattern...

 pattern, the mineral has been considered to have a carbyne

Carbyne

In chemistry, a carbyne is a monovalent carbon radical species containing an electrically neutral univalent carbon atom with three non-bonded electrons.- Gas phase/reactive intermediate :...

 structure, the linear acetylenic carbon

Linear acetylenic carbon

Linear acetylenic carbon , also called carbyne, is an allotrope of carbon that has the chemical structure -n- as a repeating chain....

 allotrope of carbon. A later report has called this identification, and the very existence of carbyne phases, into question, arguing that the new reflections in the diffraction pattern are due to clay impurities.

Ceraphite

It has been claimed that an identical form can be prepared from graphite by sublimation at 2700-3000 K or by irradiating it with a laser in high vacuum. This substance has been termed ceraphite.

A review cautions that "in spite of these seemingly definitive reports … several other groups have tried unsuccessfully to reproduce these experiments. Independent confirmatory work is obviously needed … and at the present time white graphite appears to be the carbon analog of polywater

Polywater

Polywater was a hypothetical polymerized form of water that was the subject of much scientific controversy during the late 1960s. By 1969 the popular press had taken notice, and by 1970 doubts about its authenticity were being circulated. By 1973 it was found to be illusory...

"—in other words unlikely, even fantastic claims were made that were not supported by the available data.

Sources

1. A. El Goresy, G. Donnay, Science 1968, 161, 363.
2. A.G. Whittaker, P.L. Kintner, Science 1969, 165, 589.
3. P.P.K. Smith, P.R. Buseck, Science 1982, 216, 984.
4. C. Nakayama, M. Okawa, H. Nagashima, Carbon 1977, 15, 434; D.J. Johnson, D. Crawford, C. Oates, 1971, 10th Carbon Conf, Bethlehem, PA, FC-18.
5. D.W. McKee, Annu. Rev. Mater. Sci. 1973, 3, 195.

External links

• Webmineral: Chaoite
• everything2: white carbon
• http://www.mindat.org/min-1207.html