These ruby crystals are from the Jegdalek ruby deposit in the Surobi District, Kabol Province, Afghanistan. This is a large deposits that is worked by over a dozen mines. The mines produce corundum in both the sapphire and ruby varieties. Ruby is the red gem variety of corundum. It is an oxide that contains the elements Al and O. This specimen consists of a marble matrix that contains several ruby crystals and some associated pyrite crystals. This piece measures 2 1/2 x 2 x 1 inches or 63 x 50 x 25 mm and the largest crystal is approximately 10 mm.