Frequently asked questions about diamonds

What is a diamond?

Diamond is the hardest material on earth. It is pure carbon crystallised under very high pressure and temperature. Such conditions are only found 150 to 200km under the earth’s surface. Volcanic eruptions push the rocks that bear the diamonds –kimberlite and lamproite – to the surface so they can be found.

Which countries are the main diamond suppliers?

Until the 18th century, diamonds were mainly exported from India. During the second half of the 19th century the first diamonds were discovered in Africa and the diamond rush started. The first diamond diggers worked individually and dug up the precious stones by hand. When the pits became deeper, large mining companies were founded that exploited the mines with mechanical equipment. Today, most industrial diamonds come from Australia and Congo. Jewellery quality stones come from Congo, Australia, Southern Africa, Russia, Namibia and Botswana.

How are diamonds dug up?

Diamonds are mined in different ways, depending on how the rocks bearing them come to the surface. Kimberlite mining involves open pit or underground mining. When erosion frees the diamond crystals from the kimberlite matrix, they are carried along by rivers. The riverbeds are dug away and the silt is sieved. This is called alluvial mining. Another mining technique is marine mining. Diamonds are found by dredging coastal strata.

Diamonds are rare: it is not unusual that 250 tons of rocks, sand and gravel are processed for only one carat of diamond. Some 100 million carats are dug up annually, of which only 20% is gem quality.

How are diamonds in the rough processed to gems?

A diamond is shaped through a long process of cleaving, sawing, bruting and polishing.

How is a diamond’s quality defined?

A diamond’s quality is defined by 4 parameters; cut, clarity, carat and colour.

What is a carat?

A diamond’s weight is expressed in carats. 1 carat equals 0.2 gr.

Why is the diamante processor’s craftsmanship so important?

Even the clearest of diamonds can loose sparkle and fire when the facets are not cut properly. When a stone is not perfectly proportioned it looses its beauty. Only the best diamonds get the Cut in Antwerp label.

What are the world’s most famous diamonds?

•  The Cullinan I is a pear shaped 530.20 carat diamond, also called The Star of Africa. It is set in the British crown jewels and can be admired in the Tower of London.
• The Koh-I-Noor. This oval cut 108.93 carat stone, also referred to as Mountain of Light, is one of the oldest diamonds. It was found in India and is also set in the crown jewels that can be admired in the Tower of London.
• The Hope is a blue 44.50 carat diamond with a remarkable brilliance. Legend has it the stone brings misfortune. It can be admired in the Smithsonian Institute in Washington.

What is the economic importance of Antwerp as diamond capital?

Conveniently located in the middle of Europe, Antwerp can be reached by car, plane and train. Over 50% of the world’s diamonds pass through here.

What is so special about Antwerp’s diamond district?

The Belgian diamond district is tightly packed with bourses, shops, workplaces and offices. The Jewish and Indian community control most of the diamond market, but visitors will be surprised by the variety of people they find in the diamond district. This mosaic of cultures, religions, lifestyles gives this area a colourful and multicultural feel.

What is the HRD?

The HRD is the central organisation for looking after the interests of the diamond traders, industry and customers.

What is the difference between a diamond and a brilliant?

A diamond is a stone, but a brilliant is a type of cut or shape. A brilliant is a material (glass, crystal, diamond etc.) cut in a particular shape with 57 facets.