Langbeinite: Gemstone Information
Langbeinite is K2Mg2(SO4)3 and usually forms as bedded masses or nodules from which transparent colourless white or grey, pale pink or pale greenstones have been faceted. The hardness is 3.5–4 and the SG 2.83. The RI for the cubic material is 1.532. Langbeinite is a principal ore of potash and is mined from marine salt deposits. Commercial quantities are mined at the Carlsbad potash district, Eddy County, New Mexico, USA.