Ruby — specimen 0147, photo © NMNHS
Weight: 0.02 ct; size: 1.96 | 1.93 | 1.20 mm; shape: round; colour: medium dark purple; strong; clarity: eye clean; cut: excellent; treatment: heating.
Small, very clean specimen; excellent brilliant style cut. Source: David Weinberg, Multicolour Gems Ltd
More information from ‘Classification’
A red, gem variety of corundum. The red colour is caused by minor amounts of trivalent chromium replacing aluminium in the crystal structure.