By: Floro Mercene
It is estimated that a total of 100 million carats of 90% gem quality diamonds have been produced from the onshore deposits to date. Mining is still occurring and new deposits are being discovered and put into production, however, these mines are gradually being exhausted.
Geologists realized that because diamonds could be found in Namibia’s Orange River, there was a good chance they could also be detected at sea, swept there by the current. In the 1990s, the first commercial vessels were deployed into the Atlantic in search of diamonds. Now, more than 90 percent of Namibia’s diamond-related revenue comes from offshore finds.
Diamonds are the hardest substance known to exist, but they are brittle when fractured and inclusions exist in their structure. All of the erosion and weathering processes the diamonds go through cause a great deal of stress on the structure. As a result, many of the imperfect stones are destroyed during their journey from the kimberlite to the ocean. Subsequently, marine diamonds have a remarkable high ratio of gem quality diamonds – as much as 95%. This ratio is much greater than that of land based kimberlite mines, and in general, leads to higher per carat prices obtained from diamonds recovered from the sea.
Environmental groups have raised concerns about the offshore mining operations. Dredging of any kind pulls up the ocean floor resulting in widespread destruction of marine animal habitats, as well as wiping out vast numbers of fishes and invertebrates. When ocean floor is mined, a cloud of sediment rises up in the water, interfering with photosynthetic processes of phytoplankton and other marine life, in addition to introducing previously benign heavy metals into the food chain. As minerals found on land are exploited and used up, mining of the clean floor will increase.