Talk:Augite

Geology High‑importance

	Geology portal Talk:Augite is part of WikiProject Geology, an attempt at creating a standardized, informative, comprehensive and easy-to-use geology resource. If you would like to participate, you can choose to edit this article, or visit the project page for more information.GeologyWikipedia:WikiProject GeologyTemplate:WikiProject GeologyGeology articles
High	This article has been rated as High-importance on the project's importance scale.

Rocks and minerals High‑importance

	Earth sciences portal Augite is part of WikiProject Rocks and minerals, an attempt at creating a standardized, informative, comprehensive and easy-to-use rocks and minerals resource. If you would like to participate, you can choose to edit this article, or visit the project page for more information.Rocks and mineralsWikipedia:WikiProject Rocks and mineralsTemplate:WikiProject Rocks and mineralsRocks and minerals articles
High	This article has been rated as High-importance on the project's importance scale.

Untitled

The Chemical formulas listed for Augite in the sidebar and the main text seem to contradict each other. Which is correct?

Hum, they both seem to be incorrect. The nomenclature of the pyroxenes is defined by Commission on New Minerals and Mineral Names of the International Mineralogical Association (final report)and Augite is a "quadrilateral" pyroxene, space group C2/c and "main composition" (Ca,Mg,Fe²⁺)₂SiO₃. It is still named augite if it has up to 20% of (NaFe³⁺) or (NaAl) component (more than this and it is aegirine-augite or omphacite, respectively) less then about 20% Ca leads to a change in space group (to P2₁/c) and then it's called pigeonite. 45-50% Ca and you are in the diopside - hedenbergite solid solution. This is not to say that you cannot have other elements in an augite crystal - but they are not a necessary component so should not be listed in the chemical formula (but noted elsewhere on the page). And don't take my percentages too literally, you have to do some interesting normalisations - and the normalisations are different for the Ca-Mg-Fe and the (NaAl)-(NaFe³⁺)-(Ca,Fe,Mg) plots. Andreww 20:52, 19 November 2006 (UTC)augite has a density of 5.5-6[reply]

Looks like there's a typo in the infobox code. Eddietoran (talk) 23:13, 1 December 2008 (UTC)[reply]

Fixed. Vsmith (talk) 03:35, 2 December 2008 (UTC)[reply]