Seraphinite
Seraphinite is also known as clinochlore of the Chlorite Group. The lovely dark green color is enhanced by a silvery and feathery shimmer caused by mica inclusions. Seraphinite was named for seraphim, the highest order of angels, because of the feather-like appearance of the chatoyant fibers in the stone.
Chemistry: Magnesium iron aluminum silicate hydroxide ♦ Group: Chlorite ♦ Color: Dark green ♦ Luster: Pearly to vitreous ♦ Transparency: Transparent to translucent ♦ Crystal system: Monoclinic - prismatic ♦ Moh's hardness: 2 - 2.5 ♦ Play of color: Chatoyant ♦ Localities: Notably Russia, but many other localities worldwide