Two hundred fifty round mixed cut natural tanzanites exact total weight 20.77ct., clarity is slightly included, type I, medium dark, very slightly grayish, bluish violet color, (GIA bV 6/3), cut is good. Transmitting light with a minimum of distortion, transparent. Naturally occurring internal & external characteristics are present. Color grade is an average for the group. Tanzanite is a very rare gemstone that is only found in the country of Tanzania. Originally discovered in 1967. Tiffany & Company, named the stone Tanzanite. It is found in the Usumburu Mountains that border the Umba Valley of northern Tanzania. Tanzanite occurs in gray, brown, violet, blue, reddish-purple, & green. The gem is interesting because of its exceptional pleochroism. Rotated in different directions a tanzanite will exhibit multiple changes of color. Tanzanite has a low tolerance to ultrasonic cleaning, and should not be cleaned using this method. Westfield Appraised at $2,000.00.