Sodalite

Hardness: 5.5-6 (Mohs). Color: Royal blue, grey, or purple, often with white calcite veining. Luster: Vitreous to greasy. Crystal structure: Cubic (dodecahedral). Cleavage: Poor. Specific gravity: 2.27-2.33.

Formed in silica-poor igneous rocks (nepheline syenites and phonolites) or pegmatites. It forms as a product of late-stage crystallization from magma. Significant deposits date back to various geological eras from the Precambrian to Cenozoic.

Primarily used as an ornamental gemstone for beads, cabochons, and sculptures. In industry, it is sometimes used as a pigment or for decorative architectural tiles. It is a highly popular mineral for metaphysical and rock collecting.

Sodalite was first discovered in Greenland in 1811 but became popularly known as 'Princess Blue' after Princess Margaret of England visited Canada and chose the stone for interior decor. It is often mistaken for Lapis Lazuli, but unlike Lapis, Sodalite lacks the golden pyrite inclusions.

Field Identification: Blue color with white streaks, lack of pyrite, and its relatively low density. It often fluoresces bright orange under UV light. Common locations: Bancroft (Ontario, Canada), Namibia, Brazil, and Russia.