Aquamarine Mining

by Sheweta Dhanuka

The mining process starts from carrying out the geological site investigation and environmental impact assessment (EIA) of the mines that might offer aquamarine gemstone. Then, the landform is defined by the gently moving the surface with a smooth wave like motion and is raised above the sea level. This is referred as Geomorphology.

Aquamarine is " The Gem of the Sea ". It is a light bluish green precious stone. In Latin, 'aqua refers to water' while ' mare means sea' so together when we join 'aqua' and 'mare' it becomes aquamarine. Therefore, aquamarine means sea water. As the name suggests, it possess all the different shades of the sea water - light blue colour to dark with the touch of green in all the possible variations.

With the increase in the size of stone, the colour becomes more light and transparent. Aquamarine contains tiny amount of iron, which is responsible for giving it the colour. Sometimes it is heated or irradiated to get the desired colours from the pale aquamarine crystals. The price of the stone rises with the intensity of it's colour.

The premier source of aquamarine gemstones having dark blue shades to lighter ones is Madagascar. Gemstone's country Brazil, supplies good quantity of aquamarine stones. Other aquamarine mines are found in the African countries of Tanzania, Kenya, Mozambique and Nigeria. This gemstone is procured from the island of Sri Lanka, USA and Russia too.

Also mines at Gilgit in Pakistan and few parts of Afghanistan holds large amounts of aquamarine. Mwami, Hurungwe, Pfungwe and Mtoko are yet other sources situated in different parts of the world. All the mines are mostly above the sea level. The mining process starts from carrying out the geological site investigation and environmental impact assessment (EIA) of the mines that might offer aquamarine gemstone.

Then, the landform is defined by the gently moving the surface with a smooth wave like motion and is raised above the sea level. This is referred as Geomorphology. The identified area contains precambrian metamorphic rocks under it. These rocks are composed of many minerals like quartz, feldspar, mica, garnet, biotite etc. And it holds many gemstones within it. Metamorphic rocks comprises some veins called as Pegmatite veins that host aquamarine crystals.

These veins are sheared and varies from 10m to 40m in thickness. Aquamarine crystals are of cabochon to facet grade varieties and are quite clear bearing few inclusions. Aquamarine mineralisation occurs within the pegmatites veins. The centre of the pegmatite, being massive is fractured and banded. The veins are fractured through opencast mining method using pneumatic tools.

Compressor, jack hammer, picks, shovels, chisels, ladders, etc are few to name. The mining then is augmented by a bulldozer to mine the aquamarine. Once the gemstone is free of the rock, it is collected and cleaned off with the water. It is crucial to mention that aquamarine mining is quite environment friendly. Toxic and environment-unfriendly chemicals and materials like mercury and cyanide are not used for mining of aquamarine. These are used in mining of gold and base metals.

As learnt above, the metamorphic rock containing aquamarine is braked apart into large pieces with the tools that inserts the air/gas pressure inside the rocks. With the pressure the rocks splits, gems are procured and later washed with water. Thus, mining is simple having no harmful or adverse effects. And also after exhausting the reserves, water is pumped from the pits and purified using chlorine.

The pits are filled with waste of rock. Above it, a layer of soil is laid having the thickness of 2m to 4m. After the soil gets settled, grass, relevant trees and plants are planted. The vegetation is taken care off to ensure growth for couple of years. Other wastes, such as plastics, waste paper, metal cans etc., is collected in separate metal boxes and later transported to recyclers or dumped at dumpsites. In case any petrochemical pollutant passes to water stream then the streams are well cleaned. In all, after the work is done the place is well organized and regains it's natural look.

Aquamarines collected from the mines are called as rough aquamarine. These are then sorted for size, shape and colour. After the sorting, it undergoes "gem processing" - the most critical step. The process of transforming the "rough" gemstones into beautiful and attractive gems takes lot of experience, hard work and potential. In order to optimize the rough, it is cut into long and thin slabs. Usually, aquamarines are free from inclusions and fractures so it proceeds directly to the next stage of gem processing. But, in case it has any fractures then those are removed with a diamond saw blade and the process is called sawing.

In the next stage the stones are outlined on the slab and the shapes are cut. It being a resistant stone, cutters give new and modern cuts. This process is called as pre-forming. The pre-forming is done on diamond grinding wheels lubricated by water. After getting the shape sometimes aquamarine is coloured by the colour centers. Mostly, this gemstone posses natural blue green to light sky blue colour. Thus, no further colouring is required. But, when the stone is yellow or pale, it is heat treated to produce the demanding bluish green colors. The heat treatment is performed in specialized laboratories by the experts. Thus, the colouring results are stable and permanent.

In this way aquamarine completes a long journey from metamorphic rocks to the showrooms to be part of our jewelry. It is really a valuable stone that used to be considered as the treasure of the mermaids of the sea. Aquamarines are widely used in all the jewelry items making women more beautiful in the entire world. So here is just one small tip- when making the purchase of aquamarine jewelry look for the light sparks it emits in daylight. The sparkle should be bright and colourful. So happy buying and enjoy wearing the treasure of the sea !!!!

 
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