Amethyst — specimen 0467, photo © NMNHS
Weight: 0.45 ct; size: 5.41 | 5.37 | 3.40 mm; shape: octagon; colour: light violetish blue; strong; clarity: eye clean; cut: excellent; treatment: none.
Very clean specimen; design ‘Eight’ 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.