Dattaw-upper, Dattaw-taung (Dattaw hill), Mogok Valley, Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar
On the hilltop and on the adjacent slopes, rubies and spinels are mined from the primary ruby-bearing marble deposits. Scapolite, diopside and sphene are also found. In 1999, on the northern spoles of Dattaw several illicit hard-rock mines were operating producing mostly ruby and spinel. In 2001 these mines were legalized and the volume of gem mining operations increased.A fracture-filled deposit and a primary deposit is situated at Pyar-swe-lu (22°57'22"N. 96°31'12"E.) where the ruby-bearing bands are white, greenish-bluish and yellowish with medium to fine grained texture. Scapolite and phlogopite mica are found as accessory minerals in the bands. Rubies are mined using loo-dwin and gwè-dwin mining methods.
The mining area of Upper Dattaw is famous for large, fine quality ruby and spinel crystals. Some rubies found in the marble matrix are of a fine red color and high luster, making them exquisite mineral specimens.
Ref: Ted Themelis (2008) Gems and Mines of Mogok, p. 201