Cordierite is a mineral that belongs to the group of silicate minerals known as the cyclosilicates. It is primarily composed of magnesium, iron, and aluminum, with chemical formula (Mg,Fe)2Al4Si5O18. The mineral is named after the French geologist Pierre Louis Antoine Cordier, who first identified it.
Cordierite has a distinct orthorhombic crystal structure and typically forms in contact or regional metamorphic rocks such as slates, gneisses, and hornfels. It often occurs in association with other minerals like quartz, garnet, and muscovite. The mineral can display various colors depending on impurities present, with common shades including gray, pale yellow, green, or blue.
This mineral possesses several desirable physical and chemical properties. It has a relatively low density and light blue color, making it popular as a gemstone, especially when cut en cabochon. Cordierite also exhibits a high refractive index, giving it a brilliant appearance when properly faceted. Additionally, it has a moderate hardness and good cleavage, making it suitable for various jewelry applications.
Aside from its aesthetic uses, cordierite has industrial significance as well. It possesses excellent thermal stability, a low coefficient of thermal expansion, and high resistance to thermal shock, making it a valuable component in the manufacturing of kiln furniture, refractory ceramics, and catalyst supports.
In summary, cordierite is a cyclosilicate mineral with a distinctive orthorhombic crystal structure. It is commonly found in metamorphic rocks and is used both for its aesthetic value as a gemstone and its industrial applications due to its unique thermal properties.
