Sodalite

Introduction

Sodalite is a rich royal blue Tectosilicate mineral widely used as an ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite is a member of the sodalite group with hauyne, nosean, lazurite and tugtupite.

Discovery and Name

Sodalite was first discovered by Europeans in 1811 in the Ilimaussaq intrusive complex in Greenland. The name 'sodalite' comes from the Greek word 'soda' and 'lithos', which means 'salt stone' due to its sodium content.

Properties

Sodalite is a rich royal blue mineral widely enjoyed as an ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite is a member of the sodalite group with hauyne, nosean, lazurite and tugtupite.

Close-up image of a polished sodalite gemstone showing its characteristic deep blue color and white veins.

Chemical Composition

Sodalite's chemical formula is Na4Al3(SiO4)3Cl, and it belongs to the cubic crystal system. It is a feldspathoid and a member of the sodalite group with hauyne, nosean, lazurite and tugtupite.

Occurrence

Sodalite is found in igneous rocks that crystallized from sodium-rich magmas. This is the origin of the name 'sodalite'. Its blue color is mainly from the presence of titanium and, to a lesser extent, iron. The intensity of the blue color is determined by the amount of titanium present in the mineral.

Uses

Due to its stable and vibrant blue color, sodalite is valued as a gemstone and ornamental stone. It is often used for carvings and some jewelry pieces. Sodalite is also used in inlay work and as a pigment in paints.