This gem belong to the plagioclase –feldspar group, an isomorphous solid solution series. At one end we find Albite containing sodium but no calcium; at the other end there is Anorthite containing calcium but no sodium; the intermediary members are Oligoclase, ANDESINE, Labradorite, Bytownite. The hardness is 6-6.5 from the Mohs scale. This material has been sold to me as African origin. The color is light green-yellowish, but there are also green and red variety containing copper.
Size: 16.8x12x7 mm.
Weight: 8.07 ct.