sodalites

Sodalite is a tectosilicate mineral with the chemical formula Na8(Al6Si6O24)Cl2. It is a member of the feldspathoid group, characterized by its relatively low silica content. Sodalite is known for its distinctive blue color, although it can also occur in other shades such as white, grey, yellow, and green. The blue color is often attributed to the presence of sulfur, and can deepen upon exposure to light. It is typically found in massive form, with a vitreous to greasy luster.

The mineral was first discovered in 1806 in Ilimaussaq, Greenland. It is a relatively uncommon mineral, often found in igneous rocks like nepheline syenites and other alkali-rich, silica-poor magmas. Sodalite deposits are also found in various locations worldwide, including Brazil, Canada, Namibia, and the United States. Its hardness is between 5.5 and 6 on the Mohs scale, making it moderately hard.

Sodalite is primarily used as an ornamental stone and a gemstone. Its attractive blue color makes it popular for carvings, cabochons, and beads. It is also occasionally used in small decorative objects and inlays. While not as widely used as some other gemstones, its unique appearance ensures its place in mineral collections and jewelry. Sodalite is sometimes confused with lapis lazuli due to their similar blue coloration, but they are distinct minerals with different chemical compositions and physical properties.