sodalite

{{Infobox mineral | name = Sodalite | category = Tectosilicate minerals | group = Feldspathoid group, sodalite group | boxwidth = | boxtextcolor= #FFFFFF | boxbgcolor = #253668 | image = Sodalith - Rohstein.jpg | imagesize = 260px | caption = | formula = | IMAsymbol = Sdl | strunz = 9.FB.10 | system = Cubic | class = Hextetrahedral (3m) H–M symbol: ( 3m) | symmetry = P3n | unit cell = a = 8.876(6) Å; Z = 1 | color = Rich royal blue, green, yellow, violet, white veining common | habit = Massive; rarely as dodecahedra | twinning = Common on {111} forming pseudohexagonal prisms | cleavage = Poor on {110} | fracture = Conchoidal to uneven | tenacity = Brittle | mohs = 5.5–6 | luster = Dull vitreous to greasy | refractive = n = 1.483 – 1.487 | opticalprop = Isotropic | birefringence = | pleochroism = | streak = White | gravity = 2.27–2.33 | melt = | fusibility = Easily to a colourless glass; sodium yellow flame | diagnostic = | solubility = Soluble in hydrochloric acid and nitric acid | diaphaneity = Transparent to translucent | fluorescence = Bright red-orange cathodoluminescence and fluorescence under LW and SW UV, with yellowish phosphorescence; may be photochromic in magentas | references = | var1 = Hackmanite | var1text = Tenebrescent; violet-red or green fading to white }}

Sodalite ( ) is a tectosilicate mineral with the formula , with royal blue varieties widely used as an ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite is a member of the sodalite group with hauyne, nosean, lazurite and tugtupite.