Yuksporite

Yuksporite was originally thought to be orthorhombic, space group unknown. == Appearance ==

The mineral is brownish pink, rose pink or yellowish in color, with a silky to vitreous luster and a nearly white streak. It occurs in semi-transparent fibrous, scaly or lamellar aggregates up to 10 cm across. == Properties ==

Yuksporite is a biaxial mineral, but most authors do not specify whether it is (+) or (-); the Handbook of Mineralogy gives it as (+). All agree, however, that the refractive indices are Nx = 1.644 and Nz = 1.660 (with Ny unspecified), which are larger than those for quartz, but similar to those for tourmaline. Yuksporite shows pleochroism, with X pale rose-yellow, and Y, Z rose-yellow. It has a hardness of to 5, between fluorite and apatite, and specific gravity 3.05, similar to fluorite. It exhibits barely detectable radioactivity. == Occurrence and associations ==

The type locality is the Hackman Valley, Yukspor Mt, Khibiny Massif, Murmanskaja Oblast', Northern Region, Russia, and type material is conserved at the Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, catalogue number 25847. The only occurrences reported by Mindat.org are in Russia. At the Khibiny massif it occurs in veins in nepheline syenite associated with titanite, pectolite, astrophyllite, biotite and aegirine. At the Murun Massif in the Sakha Republic it is associated with aegirine, kalsilite, potassic feldspar, titanite, lamprophyllite, wadeite and tausonite. ==References==