Mogok – the mines & people
(Mogok has become famous for its ‘Pigeon blood’ rubies)
Within the gemstone mining industry, Mogok is unique for the variety of types of production found here, each tailored for the local geology. These include alluvial mining of the gem-bearing gravel, known as byon, and the hard rock mining of spinel and ruby from the marble deposits themselves. Mogok has been an active mining region for many centuries so today most of the easily reached byon on the valley floor has long since been exploited. Consequently, the main focus of most present mining activity is upon the hillsides and mountains around Mogok and Kyatpyn and their hinterlands. A variety of different mining techniques can be observed within a very short distance, including alluvial, open pit, cave and crevice, vertical shaft and tunnel hard-rock mining. The gem-bearing gravels were more commonly found on the wide valley floors, notably around Mogok and Kyatpyin, where the precious gem-rich gravel layers were found once the overburden was removed. In the case o the open-pit mines, huge marble boulders have to be removed in order to reach the gem-bearing gravels underneath, which frequently conceal high concentrations of gemstones. Sometimes the boulders themselves are crushed in the pursuit of ruby and spinel within them. Over the past decade or so mining in the Mogok has increased in scale and the use of heavy excavation equipment to remove overburden in vast quantities has increased by a factor of four.
(Much of the work is still done by hand)
The ingenuity of the local gem miners is quite astonishing. One technique they have developed involves weaving men and equipment along the line of fissures, caves and crevices in the marble, thus avoiding the heavy lifting, time and expense of removing the large boulders prior to digging for the gem deposits. In some cases these semi-natural tunnels into the earth run for several miles and reach depths of many hundreds of metres. What is more, these processes have proved highly successful in terms of penetrating the earth to reach the richest gem concentrations of all. However, these successes have not come without a terrible human price as they produce very dangerous working conditions in which rock falls and accidents have maimed or killed many labourers. In recent times the safety records have improved as the Myanmar (Burma) government begin to develop more effective health and safety legislation and enforcement. In areas where the geology does not permit the exploitation of natural routes into the earth, the more familiar tunnel mining practices have been adopted by cutting through the rock and removing rough deposits to be crushed, washed and sorted for gems. The use of explosives to expedite the removal of rock to gain access to the deposits is a commonly practiced but risky operation, as it can crack and fracture the stones themselves but the miners have developed techniques that minimise the risk of this.
(The results of this effort are astonishing!)
Every mine needs water for its wash plants in order to separate the valuable material from the worthless rock in which it is naturally found. The basic principle behind washing goes back to ancient times and effectively relies upon the fact that gems are of a higher density than the lighter waste material, which is washed away in the process. This is often facilitated by jigs, which are pieces of equipment that separate ore from gem crystals and were originally developed by Australian tin miners, prior to their employment within the gemstone industry. The Burmese are renowned for their warm welcome and this is especially noticeable in Mogok, a fact that has aided foreign mining interests operating in this region for many years, other than during the period of stratocratic military rule (1962-2011). Most of Mogok’s indigenous inhabitants are Shan but over the ages precious gem mining has attracted people from far and wide to this enticing region and Myanmar as a whole has become one of the most ethnically diverse countries in the world. It includes those of Shan, Burmese, Lissu, Karen, Kachin, Chinese and Nepalese decent, amongst others. Many of the native Nepalese are of Gurkha descent, having arrived in Burma with the British when the country was under colonial rule and the British made good use of these excellent fighting men by employing many of them as guards on the ruby mines. Many of their descendents are still involved in the Myanmar gem trade to this day, as miners, cutters and traders.
(Stunning scenery can be found in Mogok)
The geology and topography of the Mogok region is truly fascinating and it is one of the most intriguing and diverse gem mining environments on earth. It is characterised by marble pinnacles, blackened by millennia of weathering and the weathering process also plays a role in the gemstone production in Mogok. This is because marble is an intricate part of much of the formation of ruby and spinel and the two are weathered together and transported with the marble, concentrating in gravels, or byon. Ruby and spinel are formed mainly by metamorphic events, as part of the process that build mountain ranges. When India collided with Asia the tremendous force of that collision created some of the largest areas of tectonic uplift on earth, within which the conditions facilitated the creation of many gemstones, including ruby, sapphire and spinel in what is now modern day Myanmar. Ruby and spinel are most commonly found in marble and the huge geological forces that took place in this region many millions of years ago produced vast quantities of this gemstone ‘incubating’ rock. Spinel is created by the interaction between fluids and marble deposits causing reactions that free elements including aluminium, chromium, magnesium and vanadium, which then crystallise to form the gem. When magnesium is not present in this mix, rubies form in the cavities that result from the dissolution of the sale from the evaporite beds. The chance that a fine ruby, spinel or other gemstone will form is also reliant upon the slow cooling process that follows and the space and time for the crystal to grow, very rare combinations that are abundant in Mogok.
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