Auk-inbyae (Lower Open-Pit), Kyauk-Pyat-That, Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar
The mining sites are situated at the edge of the Yadanar-kaday-kadar mine facing the Kabaing valley. In mid-1990s the gems concessions were worked intensively and produced transparent rubies and sapphires of faceting grade. Star rubies and star blue sapphires of all qualities and sizes were often found. In 1993 a 50-carat silky ruby was the most valuable gem found in this mine. Low quality, silky, translucent to opaque, cabochon-grade rubies and blue sapphires are frequently recovered, some of them up to 300 grams.Blue-pink parti-colored opaque sapphires are found. Color-shift sapphires are frequently encountered that appear blue in daylight and pink by incandescent light, but true color-change sapphires are never found. Most of these sapphires are of low to medium quality, opaque to semi-translucent, most suitable for cutting into cabochons. Few gems are transparent enough to be faceted, most of these small in size (less than 2-3 ct). Some of zircons are large and of high quality.
These gems are recovered in a small-scale open-pits, using pulsating jigs. In 1999 there were 5 joint ventures mining ruby and sapphire from the alluvium. In 2002 the mine was closed.
Ref: Ted Themelis (2008) Gems and Mines of Mogok, p. 262