Khmaralite, a new beryllium-bearing mineral related to sapphirine; a superstructure resulting from partial ordering of Be, Al, and Si on tetrahedral sites

Khmaralite, Ca (sub 0.04) Mg (sub 5.46) Fe (super 3+) (sub 0.12) Fe (super 2+) (sub 1.87) Al (sub 14.26) Be (sub 1.43) B (sub 0.02) Si (sub 4.80) O ₄₀ , is a new mineral closely related to sapphirine from Khmara Bay, Enderby Land, Antarctica. It occurs in a pegmatite metamorphosed at T> or =820 degrees C, P> or =10 kbar. The minerals surinamite, musgravite, and sillimanite associated with khmaralite at Casey Bay saturate it in BeO, and thus its BeO content could be close to the maximum possible. Optically, khmaralite is biaxial (-); at lambda = 589 nm, alpha = 1.725(2), beta = 1.740(2), gamma = 1.741(2), 2V _meas = 34.4 (1.8) degrees , v>r strong, and beta