Mayne-taung (Red Ground Hill), Myeme (Black Earth), Marble Ark, Mogok Township, Pyin-Oo-Lwin District, Mandalay Region, Myanmar
It is a natural large fissure situated at the bottom of the ridge, at the foot of Kolan hill. Rubies and red spinels are recovered from the primary rock through tunelling schemes. Rubies and fewer sapphires are also found in numerous loos (twisted holes), mixed with detrital sand and gravel.Ref: Ted Themelis (2008) Gems and Mines of Mogok, p. 227