In addition, the peraluminous minerals andalusite, cordierite and muscovite. It is a group of metamorphic minerals - sillimanite, kyanite and andalusite. It occurs commonly as an alteration product of corundum, andalusite and other aluminous minerals. Characteristic minerals include andalusite, biotite and cordierite. Minerals such as staurolite, andalusite and garnet are commonplace in these older formations. Sillimanite is one of three aluminosilicate polymorphs, the other two being andalusite and kyanite. Examples of peraluminous minerals include biotite, muscovite, cordierite, andalusite and garnet. Typical associated minerals include&colon; kyanite, andalusite, topaz, mica and quartz. The county has several mineral resources such as rock salt, limestone and andalusite. The mineral gosseletite, a phase of manganian andalusite, is named after him. These minerals, known as index minerals, include sillimanite, kyanite, staurolite, andalusite, and some garnet. It occurs associated with staurolite, andalusite, sillimanite, talc, hornblende, gedrite, mullite and corundum. South Africa possesses by far the largest portion of the world's known andalusite deposits. Metamorphic facies range from high-pressure kyanite to low-pressure andalusite. This includes knots of quartz and andalusite up to 25 cm in diameter.