Non Metallic Minerals

Garnet

Latin word "granum" which means "grain". Relating to the shape of the Garnet being of round shape and quite similar to the seeds of the fruit pomegranate. Garnet is also January's Birthstone.

 

 

Garnet exists in metamorphic rocks, meaning it has earlier been a formed rock that has been influenced by temperatures and pressure forces within the Earths crust.
The garnet group actually consist of seven different type of stone, they are; grossularite, andradite, demantoid, pyrope, uvarovite stones almandine, and spessartite.


Garnets possess similar characteristics as a crystals form, though have a different chemical make up. A Garnet is a stone made of a deep red transparent silicate mineral. Garnet is used as gemstones (though not a precious stone), and abrasives and polishing. Garnet is a type of mineral deposit and there is so much of it found around the world, since the bronze age. Garnet deposits can be found from the US, Austria, Pakistan, Russia Brazil, Germany, and Madagascar. Despite that the colour red appears most frequently, other garnets have been known to come in different shades of blue-green, hot orange, green, a pale to bright yellow and of earth and darker shades. Though, found to be the most common colour is a brownish-red. The colours of the garnet gemstone comprise of three elements, they are the tone, the saturation and lastly the hue.


Firstly the tone, is in relation to the shades of the colour. Being from the lightness to the darkness of the garnet, so from ranging between light, medium and dark.
Secondly, the saturation, is the degree of the garnet's colour, in turn is measured weak to strong to intense and, Finally the hue, which gives the first impact of the carnets colour. Garnet does not however, appear in the colour blue.


The Garnet has an great hardness of 7 to 7.5 on the Mohs' scale. Therefore this makes the gemstones superb to wear as jewellery. Garnets are quite tough and durable for wear and tear, and not difficult to mould into most jewellery.
Garnets don't have any cleavage, as other minerals do, therefore when they crack or buckle under stress, very sharp and irregular pieces are created.
Like all gemstones, Garnets are valued by the clarity, carot weight and cut.


How is Garnet Mined?
Garnet is mined just the same as other gemstones or minerals.
There are a various ways to mine Garnet. Open pit mining is the most common way. Open pit mining is where the soil is removed from an area, either by hand or machinery.
The rock is broken up into chip like form. This is similar basically to surface mining, which is mostly the cheapest and easiest way for most mining companies, and will only be done this way only if the rocks are close to the grounds surface.
   
Another technique of mining garnet is using the vertical dig shafts into the ground, that are supported by timber beams. Pumps are used to keep the shafts from filling with water. Miners will go down into the shafts, they will actually use a hammer and chisel to cut out the garnet and send them back up the shaft by hand. If needed machinery can be used to collect the garnet.
Garnets have also been known to be found in placer mines. These are like creeks, rivers and hollows where the crystals gather naturally then be collected by hand.


How are Garnets processed?
There is two ways of processing Garnet, they are the wet separation plant process and the dry mineral plant process.


During the wet separation process, the mined sands are pre-concentrated for easier handling. There is a concentrator and a separator which separate each heavy mineral, also any waste of brown silica. A scrubber will then wash the sand with fresh water to weaken chloride, remove any contaminants and conductivity levels. A Water Purification unit supplies the fresh water to the scrubber.
Through pre-concentration, primary classing is done at the same time to let the wet plant divide coarse, medium and fine stockpiles. The the stockpiles are then dried by using a fluid bed dryer (Fluid bed processing consists of cooling, granulation, agglomeration and coating of the product), sun dried and rotary driers.


The dry mineral processes sorts the stockpiles separately. One way is to produce qualities suited for sand-blasting whilst the other way is for water-jet cutting. The stockpiles are processed using machines like Magnetic and Roll Separators Electrostatic roll separators, Rare Earth which delete all magnetic and nonmagnetic sediments. Now the purified Garnet is arranged inline using the latest vibrating screens to several grades.


What are Garnets used for?
Garnets are used in the creation of beautiful jewellery around the world.
Garnets have other various uses, ranging from abrasives for blast cleaning in a variety of industries and in some approved oil and paint companies.
As a filtration method and as a water jet cutter. This slices through metal and granite with perfection, having less noise and dust than any other cutting techniques.
 


Australian Mines that produce Garnet

Port Gregory (WA)
The Port Gregory garnet mine in Western Australia, that was founded by Target Minerals in humble circumstances 30 years ago, is now an international company.

Balline Garnet Project (WA)
The Balline Garnet Project in Western Australia will produce a niche garnet product that will replace the use of harmful silica sand in industry.

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