In this tribute, geologist Dr John Bristow, pays his respects to fellow geologist Dr Derek Robinson.

Derek Robinson, who had a long and distinguished career at the Anglo American Research Laboratories (AARL) and De Beers and established himself as a leading expert in the field of diamond surface textures and breakage, sadly passed away in Jeffreys Bay on October 30, 2020, at the age of 78 after battling cancer.

Derek and his twin Michael were born in Scottburgh, South Africa, in 1942, and both finished their senior schooling at Kingsway High School in 1961. Derek completed his BSc Honours in Geology at the University of Natal at Howard College (Durban) in 1965, and an MSc (Geology) in 1971.  He was awarded a PhD by the University of Cape Town in 1979, and Management Development Program (MDP) by the University of South Africa (Unisa) School of Business Leadership in 1980.

THE AARL DIAMOND CONNECTION
Derek joined AARL in 1971 as a geologist and mineralogist, and soon became a skilled diamond mineralogist and specialist. In 1974, the AARL reorganised their mineralogists to support the commodity interests of the Anglo American and De Beers Group of Companies, with Derek being assigned to the De Beers Kimberlite Research Group under the leadership of Dr Bobby Danchin.

Derek rapidly established himself as a key mineralogist and diamond expert, particularly in respect of the many different surface textures and etch and growth features on diamonds from kimberlites. His studies of diamonds from Southern African primary, and subsequently secondary sources, soon spread to other parts of Africa and overseas countries such as Australia, Brazil, and Canada, where De Beers were searching for new mines. As his expertise became more widely recognised, he was frequently requested to examine diamond parcels from other companies involved in worldwide and local diamond exploration.

He was instrumental in the purchase and installation of a Jeol JSM-35 Scanning Electron Microscope (SEM) for the AARL to facilitate mineralogical research of ore and other minerals, including diamond surface studies. This research instrument allowed him to document in detail diamond characteristics from many different kimberlites worldwide for which he awarded a PhD from the University of Cape Town in 1979. In the 1970’s Derek and Dr Jeff Harris developed a diamond resorption model, which is still used today with minor modifications.

Derek also spent many hours documenting mining and processing related diamond breakage and trained a team of diamond-observers to undertake these studies on behalf of De Beers mining, prospecting and evaluation activities.  This work ensured the progressive modification and improvements to kimberlite-ore comminution and processing technologies to reduce breakage and improve diamond revenue streams. 

Aside from extensive work on diamond populations from numerous kimberlites, and kimberlite diamond mines, Derek pioneered studies of alluvial diamond populations from small alluvial mining operations on the Vaal and Orange rivers in South Africa, and along the Namaqualand and Namibian coast (West Coast deposits). This work led to the characterisation of distinctive diamond populations, allowing him to postulate that the probable primary source(s)of the diamonds from these alluvial deposits were the diamondiferous kimberlites around Kimberley and/or the alluvial diamond deposits in the Transvaal basin (North West Province). Subsequent isotope work on minerals included in alluvial diamonds both from the interior and coastal diamond deposits of South Africa and Namibia indicated that Kimberley diamonds were a principal source for the west coast diamonds, thereby confirming his initial postulation.

INTERNATIONALLY RECOGNISED DIAMOND EXPERT
From the outset of his career, Derek’s hallmark was his professionalism, systematic approach to diamond studies and powers of observation.He was highly respected by his superiors and colleagues within Anglo American and De Beers, and local and international peers, and attended many of the early International Kimberlite Conferences and regularly delivered papers on his work as it applied to diamonds and exploration methodologies. 

As a scientist. Derek was passionate about his diamond research, and meticulous and uncanny in respect of his observations, attention to detail, and interpretation of the formation and resorption of these unique minerals during their primary mantle and kimberlite formation and volcanic emplacement at the earths surface. Equally his research on the secondary transport of diamonds, and characterising of their abrasion features due to reworking in regional drainage and alluvial settings, has provided important insight and benefits for regional exploration programmes. 

Derek was a keen fisherman, an avid golfer and colourful storyteller. He is survived by his wife Melody whom he married in 1970, and sons Shaun and Martin and their families, all of whom now reside in the UK.

There are few PhD’s which have stood such a test of time in the field of diamond mineralogy, and Derek’s work has left a legacy which is as relevant today as it was in 1979.