the diamond is one of the most precious gemstones and occupies a completely extraordinary position among minerals due to its extraordinary physical properties. its name is derived from the greek word adamas, which means impossible to cancel or impossible to overpower in czech. it is the hardest known mineral in the world. it starts burning at 770°c. it burns down at 800°c.

diamonds were born at great depth in rocks called kimberlites, getting to the surface with volcano eruptions. diamonds are mostly found in the form of grains in river alluvia, where they were delivered by their original mother rocks.

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the first discovered diamonds came from deposits in india. there are big diamond deposits in various southern african countries and in brazil, siberia and austrialia.

diamonds are most often cut into the brilliant design. besides the brilliant cut, they are also cut into the shape of a rose. most valued are diamonds that are absolutely clear, of transparent colour or with a blue undertone. brilliants are weighed in carats and their prices in shops are indicated per one metric carat. the prices of brilliants are set according to their size, weight, internal clarity, colour and cut. defects are marked based on their nature: they may include, for example, carbons, ingrown elements, tears, dots of various colours, nebulae, sand, ice, inaccurate surface cuts.

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internationally, the value of the diamond is shown using four c’s:

carat (weight)

- one metric carat = 0.2 g. the designation is based on the name of carob grains of approximately the same weight, which were used for weighing gemstones long ago.

Colour

- the colour of the diamond is determined in northern light by comparing it to a piece of snow-white paper.

Clarity

- a tenfold magnifier is used to determine the diamond clarity. strange elements (inclusions) are looked for in the stones, as well as drops of liquid, gas bubbles and other impurities. only a diamond in which no strange element is found using a tenfold magnifier is considered clear.

Cut

- every surface of a cut diamond must decompose impinging light into the colours of a rainbow and reflect them back. only perfectly cut stones can do that.

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the most famous diamonds of the world

India

koh-i-nor (mountain of light) – is transparent, with a green undertone. the original cut was an irregular rose of 181 carats. since 1850 it has been among the property of the british royal family and it is set in the crown of the british crown jewels. in 1852 this rather imperfect stone was re-cut in london into the shape of a rose – octanogal lower brilliant of 108 carats. a diamond cutter from amsterdam was brought to london to do the work.

Brazil

star of the south – found in the state of minas gerias. it weighed 261 carats in its raw form. it was cut in amsterdam into a 125 ct clear brilliant.

South Africa

cullinan (star of africa) – the largest diamond known thus far was found in 1905 in a pit of the premier mine by pretoria, transwal. it weighed 3,106 carats and was named after the company director cullinan. it was as huge as a man’s fist, transparent, with a blue undertone, and of first-class quality. it is believed it was a fragment of an even bigger stone. the government of transwal gave it to english king edward vii as a gift. it was cut in amsterdam by the world-renowned company assher comp. after its internal structure had been examined for almost a year, it was split into two main pieces, which gave rise to nine big and ninety-six small brilliants with the total weight of 1,063 carats. cullinan 1-4 are set in british crown jewels and saved as part of the treasure in the tower of london.

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the most famous diamonds of the world

South Africa

cullinan (star of africa) – the largest diamond known thus far was found in 1905 in a pit of the premier mine by pretoria, transwal. it weighed 3,106 carats and was named after the company director cullinan. it was as huge as a man’s fist, transparent, with a blue undertone, and of first-class quality. it is believed it was a fragment of an even bigger stone. the government of transwal gave it to english king edward vii as a gift. it was cut in amsterdam by the world-renowned company assher comp. after its internal structure had been examined for almost a year, it was split into two main pieces, which gave rise to nine big and ninety-six small brilliants with the total weight of 1,063 carats. cullinan 1-4 are set in british crown jewels and saved as part of the treasure in the tower of London.