Bawpadan, Marble Ark, Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar
The gem mines have been operated for centuries.The principle rocks are ruby-bearing marble, ruby-titanite-diopside marble, pure marble, graphite-phlogopite marble and others. The ruby-bearing marble bands vary in width from 1.5 to 3 meters and are whitish to bluish-white with medium to coarse-grained texture. Rubies and spinels are found in the marble, in the loos (twisted holes), together with sphene, scapolite, pyrite, marcasite and hematite.
Intensive hard-rock gem mining started around 1974 and by 2000 more than 20 joint ventures were mining with no signs of its depletion.
Ref: Ted Themelis (2008) Gems and Mines of Mogok, p. 228