Diamond characteristics

Diamond is a pure crystallized carbon, in its second most stable form after graphite. Its physical properties are unique, being the material with the highest hardness and thermal conductivity known.

Although white (or more properly the absence of color) is its most common state, it can present practically all the colors of the spectrum.

Physical properties:
Hardness: 10 on the Mohs scale
Specific weight: 3.52
Conchoid fracture

Optical properties:
Color: All spectrum colors, although typically colorless.
Adamantine shine
Variable transparency, and possible presence of inclusions that give a milky appearance.

Diamond producing countries.
First of all, a clarification, since you have to differentiate between origin and provenance.

Origin means the country where the mine is located and origin is where it is marketed and handled. Thus, for example, we can have a diamond whose origin is a mine in Russia and its origin is Antwerp because this is where it has been cut and sold.

Antwerp (Belgium) is the main diamond trading place in the world, while the main deposits are in Russia, Botswana, Australia and the Republic of the Congo. 

Historically the first deposits appeared in the 11th century BC in India, and it developed massively from 1870 in South Africa.

The team of German Jeweler