brianite

{{Infobox mineral | name = Brianite | image = Brianite.jpg | alt = | caption = Small white microcrystals of brianite from the Dayton meteorite | category = Phosphate minerals | formula = Na2CaMg(PO4)2 |IMAsymbol=Bne | molweight = | strunz = 8.AC.30 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = P21/a | unit cell = a = 13.36 Å, b = 5.23 Å, c = 9.13 Å, β = 91.2°; Z = 4 | color = Colorless | colour = | habit = Anhedral grains with lamellar structure visible under polarized light | twinning = Polysynthetic on {100} | cleavage = | fracture = | tenacity = | mohs = 4-5 | luster = Vitreous | streak = | diaphaneity = Transparent | gravity = 3.0-3.1 | density = | polish = | opticalprop = biaxial (-) | refractive = nα = 1.598, nβ = 1.605, nγ = 1.608 | birefringence = 0.010 | pleochroism = | 2V = 63° to 65° | dispersion = | extinction = 2 to 3° from lamellae | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Brianite is a phosphate mineral with the chemical formula Na2CaMg(PO4)2. It was first identified in an iron meteorite. This mineral is named after Brian Harold Mason (1917–2009), a pioneer in meteoritics.