Seraphinite is a trade name for a particular form of clinochlore, a member of the chlorite group. The dark green color of seraphinite is enhanced by a silvery and feathery shimmer caused by mica inclusions. Seraphinite was named for the seraphim, the highest order of angels, because of the feather-like appearance of the chatoyant fibers in the stone.
The chlorites are a group of phyllosilicate minerals. The name comes from the Greek word for green, chloros, since most chlorites are green, though they also occur in white, yellow, red, lavender, or black. The most common chlorite varieties are clinoclore, pennantite, and chamosite. There are only two gem-quality minerals in the chlorite group, both types of clinochlore: Seraphinite and Kammererite.
The mineral clinochlore was first identified in 1851 in West Chester, Pennsylvania. It has since been discovered in a number of other locales in the USA, including New York, Arizona, and New Jersey. Clinochlore can also be found in other countries, including Spain, Switzerland, Russia, Turkey, and Italy.
Seraphinite, like the other clinochlorites, is a magnesium iron aluminum silicate hyroxide. It is quite a soft stone, with a hardness of 2 to 2.5 on the Moh's scale. Like all the chlorites, seraphinite exhibits perfect cleavage in one direction. When polished, seraphinite displays a pearly, vitreous luster. It has a density of 2.55 to 2.75, in approximately the same range as quartz or beryl. It's refractive index is 1.576 to 1.599, similar to emerald and aquamarine.
Due to its softness, seraphinite is mainly a collector's stone. What makes it of special interest is the silvery chatoyant fibers which form patterns similar to feathers such as one might find on a bird's wing.
The romantic name, and the association of seraphinite with angels, has gained seraphinite a reputation as a healing gem, good for nerves and brain cells.