Sodalite

Hardness of 5.5 to 6 on the Mohs scale, royal blue color often mottled with white calcite veins, vitreous to greasy luster, isometric crystal system, poor cleavage, specific gravity of 2.15 to 2.40.

Forms in igneous rocks such as nepheline syenites and trachytes from sodium-rich, silica-poor magma.

Used primarily as an ornamental stone, for carved items like this heart, in decorative jewelry, and occasionally as a gemstone.

Sodalite is the main component of the ornamental rock known as lapis lazuli, and some varieties of sodalite will fluoresce orange-pink under ultraviolet light.

Can be identified in the field by its distinct rich royal blue color combined with white calcite veining and a lack of the brassy pyrite flecks typically found in lapis lazuli. Common localities include Canada, Greenland, India, and the United States.