Silicates & Quartz
Sodalite
What it is
A deep blue mineral from the sodalite group of feldspathoid minerals. Unlike true feldspars, sodalite is undersaturated in silica and contains chlorine. Lapis lazuli is actually a rock composed largely of lazurite, another sodalite-group mineral.
How it forms
Forms in silica-poor igneous rocks like nepheline syenites and phonolites. Also found in contact-metamorphosed limestone where magma intruded carbonate rock.
Na₈(Al₆Si₆O₂₄)Cl₂
