Amethyst — specimen 0170, photo © NMNHS
Uruguay, Artigas Department
Weight: 0.93 ct; size: 6.63 | 6.62 | 4.18 mm; shape: octagon; colour: medium light bluish violet; slightly greyish; clarity: eye clean; cut: excellent; treatment: none.
Very clean specimen; design ‘Octaordinarium’, 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.