Deposit location: Korgal (Laghman)
The deposit of Korgal is famous for its extraordinary, absolutely transparent green tourmaline, so
sought after by the gems hunters. The mine is situated in a little valley on the other side of the Alingar River. From Dahaneh-Pyar, two ways of access are possible. The longer (a one and one-half day hike) consists of going back down the Alingar to the bridge, crossing the river at that point and searching for the path which takes off upstream in the direction of Dahaneh-Pyar. The second way is more dangerous but takes only a half day: at Oloswali, cross the Alingar River over the small bridge at the exit of the village, then go down the river along the slope to Korgal. Unhappily, this path is very often cut by rock cliffs that have to be jumped over, not without some acrobatics.
The deposit consists of several veins of pegmatite embedded in crystalline schists and garnet-sillimanite-biotite gneiss, all Proterozoic. The thickness of the veins is from I to 50 m, over a length of several hundred meters. Four typical mineral associations have been observed by Rossovskij et al.:
The pegmatite contains an abundance of gem crystals of tourmaline (green and sometimes pink), in places forming magnificent sheaves on muscovite. Spodumene and beryl seem less common. At Korgal, as in the other deposits, the phosphates triplite, purpurite and heterosite are rare, although eosphorite has been found. Clear, gemmy bastnaesite crystals, that we have heard about must come from the emerald mines of Pandjshir valley where some contact hydrothermal processes have affected the carbonate formation.
