Ah-chauk-taw, Bernardmyo, Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar
The mining area of Ah-chauk-taw (Dry Woods) is situated just to the north-west of the village of Bernardmyo. It was the first gem mine operated by the British after their arrival in Mogok in 1889. The current mining scheme (23°00'37''N. 96°26'50''E. at the manager's office) started in 1991, and blue sapphires are mined in open-pit, lebin, and myaw-dwin schemes.Most of the gems found in Ah-chauk-taw are of low quality, suitable only for cabochons, opaque and small in size. In November 2001 several joint ventures were in operation producing blue sapphires and fewer rubies.
Spinel, quartz (citrine, smoky, milky-white), zircon and chrysoberyl are also found.
Ref: Ted Themelis (2008) Gems & mines of Mogok, p.173