Amethyst — specimen 0753, photo © NMNHS
Weight: 0.78 ct; size: 5.83 | 5.81 | 4.35 mm; shape: octagon; colour: medium light violetish blue; strong; clarity: eye clean; cut: excellent; treatment: none.
Very clean specimen; design ‘Petal’ by Glenn & Martha Vargas, excellent cut by Tan Pen.
More information from ‘Classification’
A violet variety of quartz. The colour is caused by iron impurities in the 10s to 100s parts per million range.