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The Discovery of the Second Largest Diamond and the Importance of Diamond Weighing

The discovery of the second largest uncut diamond

The second largest diamond in recorded history has recently been discovered by a Canadian mining company in the Karowe mine in Botswana. The unbroken 1,758-carat stone weighs a staggering 352 grams and is the size of a tennis ball. It was unearthed using state-of-the-art XRT circuit technology.

The diamond is second to the famous 3,108 carat Cullinan diamond which was found in South Africa in 1905 and has since provided gems set in the Crown Jewels.

Why is diamond weighing Important?

The precise weighing of diamonds is a crucial process because they are valued in carats, which are determined according to their weight. One Carat is equivalent to 0.2 grams and stones are measured to the nearest hundredth of a carat. A single tenth of a carat could determine the difference between a £40 and a £400 jewel.

Therefore, accuracy is crucial and either a specialised Carat Balance or a precision weighing scale (which must be able to measure to the nearest 0.001g) is needed in order to provide an accurate measurement and consequently determine the correct price.

As the carat size of a diamond increases, the diamond’s price typically increases because the larger the diamond, the rarer it is. Fewer than one in one million mined rough stones are large enough to produce a finished 1 carat diamond.

Despite the importance of a diamond’s weight in determining its price, two diamonds of equal carat weight may have different costs based on other factors such as cut, colour, and clarity.

 

What other processes occur in the transformation of an uncut diamond?

For a rough uncut diamond to be transformed into a shiny perfectly shaped gem, it must be cut by a professional with sufficient expertise and equipment for the weight to remain unaltered without compromising on profit.

Firstly, the shape, the proportion of facets and the quality of cut (symmetry and polish) must all be carefully planned, which can now be done using advanced technology such as computer simulations.

Once this is done, the cleaving process will split the rough into separate pieces through mechanical sawing using a disc lined in diamond dust. The bruting process will then round off the individual pieces through girdling which involves two diamonds being placed on a spinning axle and turning in opposite directions, grinding against each other to create a smooth finish. Only a laser or another diamond can be used to mechanically cut a diamond since they are the hardest existing material.

Finally, once the rounded shape is formed, the facets of the diamond can be created by a spinning wheel which polishes the rough to create smooth and reflective surfaces.

The finished product is then inspected to ensure that it meets the specifications set by the manufacturer, and of course re-weighed to determine its final value in Carats.

 

How can Precisa’s scales be used in diamond weighing?

At Precisa, combining the latest technology with eye-catching design, we have produced a wide range of precision balances weighing up to 0.001g, which is the level of precision needed to measure diamonds and other jewels.

We also produce analytical weighing scales with an even higher readability measuring to the nearest 0.0001g

Our 360 series balance range would be ideally suited for the accurate weighing of diamonds.

 

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