Labradorite Named for its scource on Pauls island near the town of Nain labrador Canada. It is also know as spectrolite and madagascar moonstone It occurs in large crystal masses in anorthosite and shows a play of colors called Labradorescence. Other sources are norway and Finland but Canada is the largest known to date. The refractive index is 1.559 to 1.570 the mohls hardness scale is 6-6.5