The mining area has a centuries-old history of gem mining. The geology is complex consisting of calc-silicate syenite, diopside marble, ruby-bearing marble, pure marble, graphite-phlogopite marble and other rocks. Fine quality ruby
is found in the yellow marble, in contact zone (between yellow marble and intrusive rocks). Ruby, calcite and pyrite are found in the diopside skarn (between yellowish marble and syenite). Rubies of the fine quality may be found in the ruby-bearing marble bands.
In 2001 the mining area occupied about 250,000 square meters and as managed by a joint venture. The current mining scheme started in 1995 and so far has been profitable.
The Lin-yaung-chi mining camp is very well organized and equipped.
The largest ruby found was a 15-carat ruby fragment, broken from a larger 46-carat rough. During the 1990s about 900 carats of fine quality rubies were recovered from a single pocket, followed by another group of rubies weighing 48 carats.
Ref: Ted Themelis (2008) Gems and Mines of Mogok, p. 216