Kogarkoite, a New Natural Phase in the System

• Main Author: Na Son-naf-nacl
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Kola Peninsula; Lovozero; kola peninsula
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.588.2610; http://rruff.info/doclib/am/vol58/AM58_116.pdf

"Chlorine-free schairerite " was described from the Lovozero massif, Kola Peninsula, USSR, by Kogarko in 1961. A constituent of white sublimate formed at Hortense Hot Spring, Colo-rado, was found by W. N. Sharp in 1970 to yield an "X-ray powder pattern similar to that of the multiple salt Na.SOnNaF. " Both materials are identical with synthetic NagSO,F, first described by de Marignac in 1859. The name kogarkoite has been selected for the newly recognized mineral. Though the other multiple salts in the system-schairerite, galeite, and sulfohalite-are known only from evapo-rites, kogarkoite is found in igneous associations of two distinct sorts. In nepheline syenites of the Kola, it occurs with villiaumite and doubtless formed at relatively high temperature. In Colorado, kogarkoite formed at 83"C or less in hot-spring sublimate, and its principal asso-ciates are calcite, fluorite and opal. Kogarkoite is monoclinic, space grottp PL/m or P2'; a 18.073 A, b 6.949, c ll.44o, p 107"43', Z- 12; density (calc) 2.679, (meas. by Berman balance on fragments grown from melt \ 2.676; optically almost uniaxial positive; refractive indices are d = P = 1.439,'y = 1.422, Z axis ll ti02l. Morphologically, crystals appear to be rhombohedral showing a promi-nent base, which is the monoclinic {101}, and several apparent rhombohedra, The pseudo-rhombohedral character arises from subrnicroscopic intergrowth of monoclinic domains in three orientations. The atomic arrangement in a subcell is similar to that in sulfohalite.