Yebu (Hot Water), Mogok Valley, Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar
First written reference on this gem area is given in 1899 by Burma Ruby Mines Ltd. The gem mining at that time was reportedly very productive.At this time, the Yebu area is essentially an alluvial deposit, where many gems are brought down from the hillsides and concentrated on the river banks and its surrounding creeks.
Rubies are found in characteristically orientated horizontal marble layers. Ruby, blue sapphire, spinel, moonstone, danburite, quartz and zircon are recovered from the soft alluvium, using small scale myaw-dwin, open-pit and lebin mining methods.
The majority of the rubies weigh less than 3 carats. Some of dark red rubies are suitable for cutting into cabochons. When these rubies are properly heated, their appearance improves dramatically. In 2001 many mines were closed as the gem production declined.
Ref: Ted Themelis (2008) Gems and Mines of Mogok, p. 220