Haynesite, Uranyl Selenite Hydrate, New Mineral From the Repete Mine in San-juan County, Utah

Haynesite, a new mineral species, occurs as amber yellow, transparent to translucent, millimetric tablets and rosettes. Optically biaxial negative, 2V(meas) = 45-degrees, alpha = 1.618, beta = 1.738 and gamma = 1.765. Orthorhombic, space group Pnc2 or Pncm, a = 8.025, b = 17.43, c = 6.935 angstrom, Z = 2, D(calc) = 4.07 and D(meas) = 4.1 g/cm3. The strongest lines in the X-ray powder pattern [d(angstrom),(I),hkl] are: 8.01(100)100, 4.01(70)200, 3.468(60)002, 3.119 (70)051 and 2.912(80)151. An analysis obtained with an electron microprobe gave: UO2 71.81%, SeO2 17.91%, H2O (by chromatography) 8.56%, total 98.28%. The formula is (UO2)3(OH)2(SeO3)2.5H2O. Haynesite was found in the Repete mine, south of Blanding, San Juan County, Utah. It is associated with andersonite, boltwoodite, gypsum and calcite as crusts on mudstones and sandstones of Upper Jurassic age. The name honors Patrick Haynes, who discovered the new species.