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Crystal chemistry of Pb- and REE-rich piemontite from Nezilovo, Macedonia

An unusual REE- and Pb-rich epidote group mineral related to piemontite was found at Nežilovo, Macedonia where a mica schist with red mica, quartz, ardennite, gahnite, franklinite(?) and piemontite occurs in a metamorphic complex. This mineral is an intermediate member between piemontite, hypothetical CaPbAl2Mn(Si2O7)(SiO4)O(OH, F)-related to hancockite and allanite. Piemontite from Nežilovo is deep red, nearly black, with admantine luster and greyish-pinkish streak. The unusual mineral is brittle, with uneven fracture and without observed cleavage. The mineral is pleochoic: X=yellow-brown, Y=brown-red and Z=purple-brown

piemonite; Pb; REE; electron microprobe analysis; crystal chemistry; structure refinement; X-ray single crystal data; Nezilovo; Macedonia

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