What is Andalusite?
[[File:Andalusite - Malacheta, Minas Gerais, Brazil.jpg|thumb|Andalusite]] '''Andalusite''' is an [[aluminium]] [[Silicate minerals|nesosilicate]] [[mineral]] with the chemical formula Al<sub>2</sub>SiO<sub>5</sub>. At higher temperatures and pressures, andalusite may convert to [[sillimanite]]. Andalusite is an [[index mineral]]: it gives clues to the depth and pressures the host rock went through in the past. [[Category:Minerals]]