Konyaite, Na₂Mg(SO₄)₂ · 5H₂O, a new mineral from the Great Konya Basin, Turkey

Konyaite, Na₂Mg(SO₄)₂ · 5H₂O, a new mineral found in the Great Konya Basin, Turkey, is associated with one or more of the following minerals: bloedite, hexahydrite, gypsum, starkeyite, halite and loeweite. Synthetic single crystals of konyaite are transparent, euhedral prismatic with a platy habit flattened on {010} and elongated parallel to {101}. The mineral is monoclinic, P2₁/c, with a = 5.784(3), b = 24.026(9), c = 8.066(3)Å, β = 95.37(3)°, Z = 4. Strongest lines in the X-ray powder pattern are: 12.01(40)(020), 4.541(100)(121), 4.202(40)(121), 4.017(45)(002), 3.960(45)(012), 2.597(45)(240). D (meas.) of synthetic konyaite is 2.088(6) g/cm³; D(calc.) is 2.097 g/cm³. Konyaite is biaxial (−); refractive indices α = 1.464(1), β = 1.468(1) and γ = 1.474(1); 2V = 74(2)°, 2V(calc.) = 79°; α ║ β; γΔc = 70(2)°. Konyaite is metastable with respect to bloedite. DTA–TG curves show four endotherms at about 80, 92, 124 and 237° C due to dehydration. In addition a small exotherm is present at about 325° C. The name is for the locality.