sodalite

Short definition from Wiktionary

Noun

1. 1
   A mineral of alkaline igneous and plutonic rocks that are low in silica, of the chemical composition of sodium aluminum silicate with chlorine, Na₄Al₃Si₃O₁₂Cl. Pink sodalite is sometimes called hackmanite. Sodalite and lazurite form the sodalite Group of silicate minerals.