The area at Thurein-taung (Sun Hill) consists of a mixture of distinctly different and quite complex geological environments. The area has been noted for its huge caverns, some of which have not been fully explored and are very dangerous.
The principle rocks are syenite, gneiss and diopside marble. Open-pit, lebin
are used to recover mostly rubies
and blue sapphires
from the weathered alluvium. Gems are also recovered using loo-dwin
method. Rubies and spinels are recovered from different types of marble on the SE and NE of Thurein-taung, using gwè-dwin
. Over the years multi-level tunelling schemes were developed.
Since the discovery of rich sapphire-bearing pockets in 1962 many high quality, large size blue sapphires have been mined. Cabochon and faceting grade blue sapphires of all qualities and sizes, as well as asteriated examples, are also found.
Blue sapphires are also recovered in small pockets from the adjacent dike and skarn.
Ref: Ted Themelis (2008) Gems & mines of Mogok, p. 260
Gem list contains entries from all listed localities in region.
Localities in this Region