POWERHOUSE COLLECTION

Notes

In 1858, James R Gregory founded a mineral specimen business (later known as Gregory, Bottley & Lloyd) selling minerals and fossils.(1) After a few years, he gained a reputation as one of the best dealers in London. Gregory mounted a display at the Sydney International Exhibition in 1879 - the exhibition that preceded the establishment of the Powerhouse Museum. His exhibit featured 'mineral collections, rock collections, fossils ... models of the most celebrated diamonds and a number of precious stones' (2). It was deemed to be a well-arranged educational collection. Gregory received a Commended award for his Geological collection, illustrating Professor Geikie's Primer and Professor Bormey's Manual of Geology, and a First Degree of Merit for his fossil and mineral displays (2). In 1880 Gregory agreed to donate specimens to the Museum following his display at Melbourne International Exhibition (1880-1881) or otherwise would send them from England (3). This collection was purchased later from Gregory and shipped from England along with a number of other items in 1886. 1. TimeLine Auctions Ltd. (2020). TimeLine Auctions Est.1858: Our History. Available from https://timelineauctions.com/about-our-premises/ Accessed on 31/4/2020 2.Official Record of the 1879 International Exhibition, Sydney: Thomas Richards, Government Printer, 1881, pgs 33, 134, 370 (MAAS collection 87/371) 3. Technological, Industrial and Sanitary Museum Annual Report, 1880, Appendix III, p15. James R. Gregory and the Diamonds of Hopetown The first diamond to have been discovered in South Africa, is said to have been found in 1866, by a 15-year-old boy (Erasmus Jacobs), near Hopetown on the Orange River; the 21.25 carat diamond later became known as the Eureka [4]. Within the following years, a spattering of further alleged diamond discoveries in the region piqued the interest of international merchants and dealers. James R. Gregory travelled from England to South Africa at the behest of Mr. Harry Emanuel, a diamond merchant based on Bond Street, who was interested in the prospect of a new diamond supply. At this time, the majority of diamonds originated in India and Brazil and all diamonds had been found as alluvial deposits in rivers. Gregory conducted an examination of the district between Cradock and Hopetown, in South Africa and determined that its geology, being primarily comprised of igneous or volcanic rock, is inconsistent with what mineralogists had come to expect of diamond producing regions. He also explored a 'tributary of the Vaal River, near the junction of the Orange and Vaal Rivers', where he found many mineral specimens but no diamonds nor the minerals typically associated with them. As a result, he concluded that it was impossible for diamonds to have naturally originated from that region [1]. Gregory's inspection of the Hopetown region was merely one of the first of many such inquiries into the presence of diamonds in South Africa, before the connection between diamonds and the mineral kimberlite was discovered in 1869; only a year after Gregory published his article in Geological Magazine. Kimberlite is a volcanic rock and was so named for its place of discovery, Kimberly, South Africa [3]. Through further study of diamonds and their primary host rock, kimberlite, it is now known that diamonds are produced under great pressure and at high temperature, approximately 150 km below the Earth's surface. Diamonds are brought to the surface via volcanic eruptions [3] of alkaline igneous rock such as kimberlite and more scarcely lamproite. Alluvial diamond deposits occur only after the volcanic rock has been eroded away and the diamond deposited into a river where, prior to the 1860's, all diamond deposits had been found for over 2000 years [4]. It seems that, while Gregory conducted his investigation with the information and knowledge of the time, he was ultimately mistaken in his conclusions and perhaps did not approach the expedition with quite an open enough mind to be receptive of pending discoveries. Several articles were written and published over the year of 1869, calling Gregory out on his inaccurate findings. In May, 1869, Gregory saw fit to reply to one such article by Dr. Atherstone, retorting that his primary goal was to 'caution [...] against placing implicit reliance upon the newspaper reports' [2] which he believed to be exaggerated and misleading. Gregory also acknowledged, 'it should always be borne in mind that Geology, like many other sciences, is not infallible, and that it is quite possible that diamonds may be found in rocks where past experience has taught us they never occur, but still we find the maxim experientia docet usually holds good in diamond-prospecting as well as in that for gold' [2]. Despite the many criticisms that Gregory received for the conclusions drawn in his initial 1868 report, it was not until 1871, that non-alluvial deposits of diamonds began to receive much attention from the geological community. [1] Diamonds from the Cape of Good Hope, J.R. Gregory, Geological Magazine, Vol. 5, No. 54, pp. 558-561, (1868). [2] Discovery of Diamonds, etc., at the Cape, J.R. Gregory, Geological Magazine, Vol. 6, No. 61, pp. 333-334, (1869). [3] Laniado, E. A. (2016). How Diamond Mines are Formed, How We Find Them, and How We Decide Whether or Not to Mine Them. Retrieved May 14, 2020, from All Diamond web site: https://www.ehudlaniado.com/home/index.php/news/entry/how-diamond-mines-are-formed-how-we-find-them-and-how-we-decide-whether-or-not-to-mine-them, accessed 20.5.20 [4] Field M, Stiefenhofer J, Robey J, Kurszlaukis S (2008) Kimberlite-hosted diamond deposits of southern Africa: a review. Ore Geology Reviews 34 : 33-75. doi: 10.1016/j.oregeorev.2007.11.002, available from https://www.researchgate.net/publication/238365259_Kimberlite-hosted_diamond_deposits_of_southern_Africa_A_review, accessed 20.5.20 Natalie Draper, Curatorial Assistant and Angelique Hutchison, Curator. 2020.