925/000 Ring made in Labradorite from Madagascar

The mineral labradorite is a calcium sodium aluminum tectosilicate with the chemical formula (Ca, Na) (Si, Al) 4O8. It belongs to the feldspars. The colorless, white, gray or light green labradorite has a glass luster, a white stripe color, a perfect cleavage according to crystal plane [001] and a good according to [010]. The mean density is 2.69 and the hardness is 7. The crystal system is triclinic and the mineral is neither radioactive nor magnetic. The characteristic play of colors, called labradorisation, is caused by the light refracting on microscopic crystals of various dark minerals, which lie on the cleavage surfaces. Labradorite is usually shapeless or granular; the mineral seldom if ever forms crystals. Labradorite is undoubtedly the best known of the precious gemstones that display such a play of colors. When the stone is cut judiciously, the play of colors comes into its own even better. But the beautiful labradorization can also often be seen on the rough chunks. Few minerals change color as much as labradorite. The name of the mineral Labradorite is derived from the Labrador Peninsula in Canada, where it was first described. The stone was discovered by a priest on the east coast of the Labrador peninsula in 1780 and named after the island by him. He found a large number of erratic stones with a striking gray color that changed color to dark blue and green nuances when turning. This find aroused great interest among scientists at the time and it was found to be a soda lime feldspar or plagioclase. Labradorite is a very common feldspar in metamorphic and igneous rocks such as pegmatite. It is part of the plagioclase series (albite-anorthite). Labradorite's type location is in the Canadian Labrador Peninsula. Deposits are also found in Australia, Madagascar, Mexico, Russia, the United States and Finland.