A "Madagascar moonstone" refers to a variety of moonstone that originates from Madagascar, often characterized by a vibrant play of color, known as adularescence, with flashes of blue, silver, and sometimes even red and rainbow hues, making it a particularly desirable type of moonstone, often called "rainbow moonstone" in the gem trade; it's technically a type of labradorite feldspar found in Madagascar with a unique color display similar to traditional moonstone.
This stone is 6mm and faceted to show off its spectrum of colors!
