The mining method of ruby is mainly manual operation. Due to the harsh climatic conditions, the general excavation period is only from June to August every year, and the output is small. High-quality gem-grade faceted ruby products are generally less than 1.5ct, while curved ones are often between 2 and 2~3ct. The weight of poor quality ruby crystal can reach 5 ~ 7 kg. 20 10 saw a gem-grade "Tajikistan ruby" of about 10ct in the market, with a medium quality of 40ct.
Pamir Plateau is located at the junction of southern Xinjiang of the former Soviet Union, Afghanistan and China, and crosses Tajikistan. Geologically, the Pamir Plateau was formed in the crustal movement from Paleozoic to Mesozoic, and the collision between the Cenozoic Indian plate and the Asian plate also had a certain impact on the formation of the plateau, leading to the formation of mountains. The Pamir Plateau is generally east-west, and the main rocks are ultramafic metamorphic rocks, metamorphic sedimentary rocks, biotite gneiss, marble, calcareous silicate, quartzite and amphibole.
Geologically, the rubies in Dura Kourouma are similar to those in Zadaleka, Kimari in azad-Kashmir, Hansa in Pakistan, Gumu in Myanmar and Lu 'an in Vietnam, all of which are produced in metamorphic marble.
The mineralization of corundum generally occurs in metamorphic rocks in the middle of Pamirs, but the amount of corundum reaching gem grade is very small. Tourmaline, apatite, rutile and pyrite often appear in metamorphic rocks, but the mineral combination related to corundum varies with marble types: calcite marble contains corundum, muscovite, andalusite and biotite; Dolomite marble contains corundum and biotite
Figure 4-44 Distribution Map of Main Ruby Deposits in Tajikistan