References

 Literature Review 

 Mollah, M.Y.A. Cristobalite formation from thermal treatment of Texas lignite fly ash. Fuel (Guildford) 78.11 Sep 1999: 1277-1282. Elsevier. 05 Apr 2012.

The article Cristobalite  formation from thermal treatment of Texas lignite fly ash was an article last revised in 1999. In the article, the authors did a study on the thermal treatment of lignite fly ash to get inside to into the formation mechanism and resulting structure of the thermally treated ash. the ash in the study had main crystalline phases as mullite, hematite, quartz and cristobalite. The cristobalite found in the treated sample was on the outer region of the particles with a thermal treatment of greater then 900degrees F. In the study they found of that cristobalite crystallized instead of tridymite 'eventhough the latter is the thermodynamically stable phase because kinetics of formation is an important factor that needs consideration'.

P.                    J. Baxter1, C. Bonadonna2, R. Dupree3, V. L. Hards4, S. C. Kohn2, M. D. Murphy2, A. Nichols5, R. A. Nicholson4, G. Norton4, A. Searl5, R. S. J. Sparks2,* and B. P. Vickers4. "Cristobalite in Volcanic Ash of the Soufriere Hills Volcano, Montserrat, British West Indies." Science 283.5405 (1999): 1142-1145. Print.

The article Cristobalite in Volcanos Ask of the Soufriere Hills Volcano is basically about the volcano and the cristobalite matter inside the magma. The article also discussed the potential hazardous effect that crystallite on the ash has on human health. The authors of this article then did a study on the hazards of ash on human health and found out that there was health threats from long-term exposure to volcanic ash generated by pyroclastic flows from lava domes. This is because the silica can lead to the development of silicosis.

Amir Yeganeh-Haeri, Donald J. Weidner and John B. Parise, Elasticity of α-Cristobalite: A Silicon Dioxide with a Negative Poisson's Ratio, Science , New Series, Vol. 257, No. 5070 (Jul. 31, 1992), pp. 650-652 Published by: American Association for the Advancement of Science Article Stable URL: http://0-www.jstor.org.helin.uri.edu/stable/2877480

The article Elasticity of alpha-cristobalite: a Silicon Dioxide with negative poisson's ratio talked about the unique elasticity of alpha-cristoblite. In the article, the author discusses that there are three distinct forms of SiO2 which are quartz, tridymite and cristobalite. All three of the forms are polymorphs and have an alpha and beta. But cristobalite's alpha from is unique because it has a negative Poisson's ratio where it contracts laterally when compressed and expands laterally when stretched. At the end of the article it says that this is important because whenever a singe-crystal coeff is around, that the we can carry out a tensorial analysis of of coeff and look at an entire range of behaviors of Poisson's ratio.

Friedman, Hershel. "Cristobalite: The mineral Cristobalite information and pictures  ."              The Mineral and Gemstone Kingdom: Home  . N.p., n.d. Web. 5 Apr. 2012. <http://www.minerals.net/mineral/cristobalite.aspx>.

The mineral and Gemstone Kingdom was an website I found while looking up my mineral before writing the paper. The website was written by Hershel Friedman who has been collecting rock for since he was a kid. Even though the site was not published by a university of the government I found the information on the site to be useful with the physical properties of Cristobalite. On the site, it also tell you locations that the mineral has been found and some uses that scientist and society has for the mineral today. Over all I used this site with caution but found it to help with the general points.

Swainson, I P , and M T Dove  Dove. "Molecular dynamics simulation of alpha - and beta -cristobalite." Journal of Physics: Condensed Matter 7.9 (1995): n. pag. http://www.uri.edu/library/. Web. 6 Apr. 2012.

In the article Molecular dynamics simulation of alpha and beta cristobalite the authors talked about the two forms of cristobalite and the disorder of the beta from over the alpha form. They start off my explaining that cristobalite is a stable phase of SiO2 and when quenched below the 1743 K can exist in a metastable stat without conversion to either the tridymite and quartz. It then went on to talk about the different polymorphs of cristobalite which are alpha-C and beta-C. Throughout the paper the author talk more about the different polymorphs and the testing to see the differences in them. At the end the authors conclude by saying that the beta phase of cristobalite has no evidence of any preference fro crystallographically distinct domain and that it can be ruled out of the two studies they did in the paper.

Å imon , I., and H. O. McMahon McMahon. "Study of the Structure of Quartz, Cristobalite and Vitreous Silica by Refection in Infrared." Journal of Chemical Physics 21.1 (1953): 23-30. Print.

The article Study of the Structure of Quartz, Cristobalite and Vitreous Silica by Refection in Infrared, is about a study done on the reflection method using natural and polarized radiation on both forms of quartz and cristobalite and vitreous silicas. This was done by measuring the reflective power of the crystals and different wavelength powers that it comes off with. With alpha quartz there are strong bands at 1055 cm-1 and with alpha cristobalite the strong band is at 1095 cm-1. In the study they observed the different band that came off of the crystals and compared them to other forms.

Intensity(I/I. "Cristobalite Mineral Data." Mineralogy Database. N.p., n.d. Web. 6 Apr. 2012. <http://webmineral.com/data/Cristobalite.shtml>.

For this cristobalite site I only used the molecular weights and precent of silicon vs. oxygen.

Works Cited

Mollah, M.Y.A. Cristobalite formation from thermal treatment of Texas lignite fly ash. Fuel (Guildford) 78.11 Sep 1999: 1277-1282. Elsevier. 05 Apr 2012.

J. Baxter1, C. Bonadonna2, R. Dupree3, V. L. Hards4, S. C. Kohn2, M. D. Murphy2, A. Nichols5, R. A. Nicholson4, G. Norton4, A. Searl5, R. S. J. Sparks2,* and B. P. Vickers4. "Cristobalite in Volcanic Ash of the Soufriere Hills Volcano, Montserrat, British West Indies." Science 283.5405 (1999): 1142-1145. Print. 

Amir Yeganeh-Haeri, Donald J. Weidner and John B. Parise, Elasticity of α-Cristobalite: A Silicon Dioxide with a Negative Poisson's Ratio, Science , New Series, Vol. 257, No. 5070 (Jul. 31, 1992), pp. 650-652 Published by: American Association for the Advancement of Science Article Stable URL: http://0-www.jstor.org.helin.uri.edu/stable/2877480

Friedman, Hershel. "Cristobalite: The mineral Cristobalite information and pictures  ."   The Mineral and Gemstone Kingdom: Home  . N.p., n.d. Web. 5 Apr. 2012. <http://www.minerals.net/mineral/cristobalite.aspx>.

Swainson, I P , and M T Dove  Dove. "Molecular dynamics simulation of alpha - and beta -cristobalite." Journal of Physics: Condensed Matter 7.9 (1995): n. pag. http://www.uri.edu/library/. Web. 6 Apr. 2012.

Å imon , I., and H. O. McMahon McMahon. "Study of the Structure of Quartz, Cristobalite and Vitreous Silica by Refection in Infrared." Journal of Chemical Physics 21.1 (1953): 23-30. Print.