Published: September 30th 2011September 30th 2011
Ruby with mother rock from Hunza
Ruby with mother rock marble from Hunza Valley of Pakistan
HUNZA RUBY (Al2O3)
Ruby is a member of the mineral family corundum and it is closest is the Sapphire. The ruby is rare gem because the chromium pigments are embedded in the earth’s crust is not plentiful and also the Chromium had to meet up with the element alumina at the exact moment that crystallization actually occurred. Without these two elemental factors the ruby might not be much red color. Up to now the first rubies come from Burma. With discovery of the rubies in Pakistan and in Afghanistan, sources to rival traditional Burmese material may have been found. It is possible that Pakistan sources may yield rubies of the highest quality. The color of the small stone is equal to that of the best Burma material, larger stones have been found too, although some of these are more inclined to pinkness and opacity.
The ruby deposits in Pakistan occur in metamorphosed re-crystallized limestone marble in a narrow belt from Hunza Valley to Ishkoman that is more than 100 km in the northern areas (Gilgit Baltistan) of Pakistan. Ruby deposits are also occurring in Azad Kashmir and Astor. The Hunza ruby crystals, quite well formed, are pink to a
Ruby crystal in crystalline limestone
fine red in color. Calcite crystals, which make up the ruby bearing marble are found within the stone themselves and cause opacity.
The ruby deposits are located in the Himalayan mountain belt, which is developed during the continental collision of the Indian plate northward into Eurasian plate, MKT, Main Karakorum Thrust. They are spatially related to granitoid intrusions and are contained in platform carbonates series that underwent high-grade metamorphism. All occurrences are located close to major tectonic features during the Himalayan orogensis, directly in suture zones in the Himalayas or in shear zones that guided extrusion of the Indochina block after the collision in South East Asia. Some minerals with ruby give evidence that these deposits formed during Himalayan orogenesis.
Most of rubies from Hunza Valley are clouded and calcite is commonest mineral inclusion, since the rubies are formed in metamorphosed limestone, which is consist largely calcite. Potassium mica, phlogopite is also common inclusion forming bunch of reddish brown flakes. Yellow-brass crystals of Pyrite also found. Other internal features are cracks and parting planes directions in which the crystal may divide internally.
Spinal is a member of the cubic crystal system and has the composition MgAl2O4.
A fine red colour is obtained where a chromium impurity is present and somewhat darkish blue that is due to iron are also known, as is a plum-coloured variety. Spinel is hard mineral 8 on Mohs scale and tough without cleavage.
Pargasite is a member of the amphibole group of minerals and composition of Naca2 (Mg, Fe2+)4 Al(si2 Al2) O22 (OH)2. It crystallizes in the monoclinic system. The deep pistachio green crystals of pargasite occur in the metamorphosed crystalline marble a long with spinel and ruby in Hunza Valley. It is more abundant in the rocks and quarries a long the Hunza River. The dealers and in Karimabad Bazaar often sell them as Hunza emeralds.
Ruby, Spinel and Pargasite are found along the Main Karakorum Thrust (MKT) and these are commonly occur side by side in this metamorphosed re-crystallized marble beds, which form part of a thick sequence of meta-sediments known as the Baltit group that extended over 100 Km between the Hunza Valley ( East) and Ishkoman Valley ( West). The gems bearing marbles crop out adjacent and parallel the suture zone (MKT). The suture zone is characterized by a thin belt of green schist, serpentinite,
black slates and mylonite, exposed south of the Hunza River. These rocks have been thrust southward over the Kohistan Isand Arc sequence that is meta-volcanic along the northern slopes of Rakaposhi Mountain. The Baltit Group is consists of gem bearing marbles, garnet schist, quartz mica schists, garnet amphilbolites. The intrusives are mainly applite, granite and pegmatite dykes which criss cross the Hunza marble and adjoining Karakorum Granodiorite site.
MINES IN THE HUNZA VALLEY:
In local market where plenty of the shops are flooded with various gemstones of Gilgit-Baltistan especially Hunza Ruby also in the market of Peshawar you will find mostly the gemstone from Northern Areas (Gilgit- Baltistan) of Pakistan. There are different mines in various regions of the Hunza Valley where local people doing mining by their own ways and sell the specimen to the local market or local agents from there. From here through the local agents all these material go to Gilgit and Peshawar markets then to the international market. There is also gems cutting center in Karimabad for the cutting and polish the stones as well as in Gilgit. There was a single company, “Global Mining” was mining in Ahamedabad but last year also stopped
to work. The PMDC, Pakistan Minerals Development Co-operation, has also worked in Ganish and Ahamedabad during 1974 to 1978, also in Altit Village. According to a report of the PMDC that colour and hardness of the rubies from Ahamedabad areas are fairly good as compared to other areas of ruby bearing areas in the Hunza Valley.
• Ganish Mines
• Donaydas Mines
• Ahamedabad Mines
• Dorkhan Mines
• Hassanabad Nala Mines
“NORTH PAKISTAN ADVENTURE” organizes geological study tours in the Northern Areas of Pakistan and take you to the mines where local miners mining in various places of the Gilgit-Baltistan. You may have chance to see the way of the mining on the mountains and lives of the miners on the mines, experience of trekking, meeting with miners and dealers. You may have also contacts of the miners and local dealers of the gemstones.
Cell: 0092 333 5276586
Mr. Ishaq Ali
There are more photos below