Labrodorite

Labrodorite named after a peninsula in Canada, where it was found. It is a plagioclase feldspar. It shows a Schiller ( Labrador-essence ) in Lustrous metallic tints, often blue and green, although specimens with the complete spectrum are most appreciated. It is mainly caused by interference of light from lattice distortions resulting from alternating microscopic exsolution lamellae of high and low calcium plagioclase phases. Vitreous luster; sensitive to pleasure. Deposits are found in Madagascar., Mexico, Russia, and the United States. 

Color: Dark Grey- Black, with colorful iridescence