Ruby — specimen 0276, photo © NMNHS
Tanzania, Ruvuma, Songea
Weight: 0.61 ct; size: 6.33 | 4.36 | 2.79 mm; shape: pear; colour: medium dark strongly purplish red; very slightly brownish; clarity: eye clean; cut: good; treatment: heating.
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.