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East of Nilaw, not far from the Kolum River, is the famous deposit of Mawi where very large crystals of

spodumene (green, blue, pink, yellow and colorless), beryl (morganite and aquamarine) and tricolored tourmaline were discovered. The path from Nilaw to Mawi is relatively easy and can be covered in a half-day walk. It is necessary to cross the Koh-e-Sagoli range (altitude about 3,000 m), then descend again through the short valley of Mawi until the dumps that mark the zones of exploitation appear. It is difficult to judge the thickness of the Mawi pegmatites, but it is surely considerable. (According to Rossovskij, et al. ( 1976), the principal vein is about 40 m thick and runs for 1,200 m. ) The following paragenesis can be recognized:

Aggregates of quartz and muscovite of about 10 cm thickness first formed at the borders of the veins, in contact with the wall rocks, some with blue-green beryl crystals of large size.
Biotite and microcline with quartz, aquamarine, and black tourmaline formed next. This association is only observable in the eastern part of the deposit.
A discontinuous zone of giant crystals of quartz and microcline then formed. The beryl crystals are found only in the apophyses of the principal vein.
Then a “zone” of quartz and spodumene formed, which actually comprises local segregations with a thickness of several meters, also containing crystals of columbite-tantalite. The spodumene crystals of this “zone” are of great size (up to 2 m long)

Paragenetic stages 5 through 7 proposed by Rossovskij et al. consist of the associations albite-muscovite-quartz in various proportions, in places sugary, with concentrations of lepidolite, multicolored tourmaline and spodumene. The latter mineral seems the most sought after at Mawi. In July of 1973, 420 kg of spodumene were extracted there, and 176 kg in October-November of the same year. These figures lead one to suppose that the reserves are important. Estimates of reserves of beryl immediately exploitable at Mawi lead to a total in the vicinity of 50 tons. Tantalite and pollucite seem too dispersed to be of economic value.
On visiting several dumps, we were able to observe great plates of rock, covered with crystals of quartz, microcline and albite (cleavelandite), on which had been fixed the crystals of spodumene of which only the bases remain, individual crystals having been detached from their support by the gem hunters. However, spodumene lining cavities seemed rare and the production consists largely of isolated, free crystals that are extracted from pockets in altered pegmatite. The same appears to be true for beryl. We also found several specimens covered with little crystals of tricolored tourmaline and even colorless tourmaline (achroite). It is, however, illusory to imagine gathering beautiful crystals if one has only a geologist’s hammer. Other minerals also caught our attention, notably some pretty spessartine garnets embedded in the pegmatite and also two enormous balls of botryoidal muscovite with a maximum diameter of 30 cm but, sadly, untransportable.