Sodalite

Hardness: 5.5-6 on the Mohs scale. Color: Royal blue to deep denim blue with characteristic white calcitic or feldspathic veining/patches. Luster: Vitreous to greasy. Crystal System: Cubic/Isometric. Cleavage: Poor in six directions. Specific Gravity: 2.14-2.40.

Sodalite is a tectosilicate mineral that crystallizes in silica-poor igneous rocks, particularly nepheline syenites, phonolites, and associated pegmatites. It forms during late-stage magmatic crystallization or hydrothermal alteration.

Used extensively as an ornamental stone, gemstone in jewelry (pendants, beads, cabochons), and carved decorative objects. It is also popular in mineral collections and metaphysical lapidary crafts.

Sodalite was discovered in 1811 in Greenland but gained widespread popularity after large deposits were found in Ontario, Canada, during a royal visit in 1891, leading to it sometimes being called 'Princess Blue'. Although the handwritten note in the image says 'Agate (Chalcedony)', the visual features—mottled deep blue with white veining and lack of concentric banding—clearly identify this polished pendant as sodalite or lapis lazuli rather than agate.

Identified by its rich deep blue color interspersed with white streaks or spots of calcite/feldspar. Unlike lapis lazuli, sodalite typically lacks golden pyrite specks and is slightly less dense. Common sources include Canada (Bancroft, Ontario), Brazil, Namibia, Russia, and Greenland.