Hauyne, haüyne or hauynite was first described in 1807 from samples discovered in Vesuvian lavas in Monte Somma, Italy, and was named in 1807 by Brunn-Neergard for the French crystallographer René Just Haüy (1743-1822). It is a tectosilicate mineral with sulfate, with endmember formula Na₃Ca(Si₃Al₃)O₁₂(SO₄). As much as 5 wt % K₂O may be present, and also H₂O and Cl. It is a feldspathoid and a member of the sodalite group.