Sodalite

Hardness: 5.5 - 6 on Mohs scale. Color: Rich royal blue to dark blue with white or grey mottling/veining (calcite). Luster: Vitreous to greasy. Crystal structure: Isometric (dodecahedral). Cleavage: Poor in 6 directions. Specific gravity: 2.2 - 2.3.

Forms in silica-poor igneous rocks such as nepheline syenites, phonolites, and associated pegmatites. It crystallizes during the late stage of magmatic differentiation in alkaline magmas.

Widely used for gemstone carvings, beads, tumbled stones, cabochons, decorative items, and ornamental architectural carvings. Occasionally used as a lapis lazuli substitute.

Sodalite was first discovered by Europeans in Greenland in 1811, but became hugely popular as an ornamental stone after vast deposits were discovered in Ontario, Canada, during a visit by the Princess of Wales in 1891 (often called 'Princess Blue').

Can be identified in the field by its distinct deep blue color combined with white veins (calcite). Unlike lapis lazuli, sodalite rarely contains flecks of golden pyrite, and it frequently fluoresces bright orange to reddish-orange under long-wave ultraviolet light. Found abundantly in Canada (Bancroft, Ontario), Brazil, Namibia, Russia, and Greenland.