natural russian seraphinite mineral stone with silvery-white inclusions of mica resembling the wings of an angel

seraphinite mica mineral stone russia amulet angel wings atomic structure cat eye center chatoyancy chatoyant chlorite clinochlore concentration minerals concentric crystal aggregate crystallization crystals deep green diffraction emerald feathers gemology grown together hardness inclusion inclusions inorganic iron irregular shapes stripes lustre metallic luster mineralogy natural optical effect polished precious radial radiate russian semiprecious seraph siberia silver silvery white