‘Golconda’ diamonds found on the Indian subcontinent, were created from the enormous forces generated by the ‘Tethys Oceanic Crust’ colliding, and being subducted under the ‘Asian Continental plate’ (aka plate tectonics). Although these massive continental plates collided at the incredibly slow rate of 10 centimetres per year, this was enough force over 100s of millions of years, to create the Himalayan Mountain range, and to cause the necessary volcanic activity to create diamondiferous intrusive and extrusive igneous rock known as ‘kimberlite.’
Most of the diamonds entering Europe originated in India. In the later half of the 14th century, the diamond trade route extended from India to Bruges, Paris and eventually to the diamond bourses of Antwerp, Belgium. After Portuguese explorer Bartolomeu Dias’ 1488 discovery of the ‘Cape of Good Hope’ on Africa’s southern most tip, fellow Portuguese navigator Vasco da Gama discovered a sea route to the India and Orient by sailing around the Cape in 1498. This provided Europeans with an easier route to the Indian diamond trade, avoiding the costly and dangerous ‘Silk Road’ caravan routes.
The term ‘Golconda’ is still used (or misused) today as an indicator of very high quality diamonds. To justify the ‘Golconda’ name, diamonds must have a level of transparency and quality found only in rare, chemically pure type-IIa natural diamonds. The term ‘Golconda’ is also used as a generic term to describe higher quality diamonds with an antique cut.
