Ruby — specimen 0629, photo © NMNHS
Tanzania, Ruvuma, Songea
Weight: 0.12 ct; size: 3.11 | 2.75 | 1.80 mm; shape: hexagon; colour: medium dark strongly purplish red; very slightly brownish; clarity: eye clean; cut: excellent; treatment: heating.
Very clean specimen; design ‘Hexamixtum S 41-32’, excellent cut by Tan Pen.
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.