One electronically tested 18KT white gold ladies cast tanzanite and diamond ring. Condition is new, good workmanship. The featured tanzanite is set within a diamond bezel supported by stylized diamond set split shoulders, completed by a two millimeter wide band. Trademark is UCG. Identified with markings of "18K 750". Containing: One prong set oval mixed cut natural tanzanite, measuring 11.70 x 7.80 x 5.70mm, approximate weight of 3.94ct., clarity is eye clean, type I, medium dark, moderately strong, bluish violet color, (GIA bV 6/4), cut is good. Transmitting light with no distortion, transparent. Graded in the setting. Tanzanite is a very rare gemstone that is only found in the country of Tanzania. Originally discovered in 1967. Tiffany and 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, and 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. Forty-two prong set round brilliant and baguette cut diamonds approximate total weight of 42 Stones = 1.13ct. Graded in the setting.Clarity VS-2 to SI 2Color F-H Total Weight of Colored Stones 3.94ct.Total Weight of Diamonds 1.13ct.Total Weight of Ring 6.33 gm (14966)