THE DIAMOND DEPOSITS OF KALIMANTAN, BORNEO By L. I<. Spencer, S. David Dikinis, Peter C. Keller, and Robert E. IZane The island of Borneo is one of the oldest orneo is an island of the Indonesian Archipelago known -and least reported on -sources of B located in the western Pacific Ocean. It is divided into diamonds. Although diamond mining his- the Malaysian states of Sarawak and Sabah and the British- torically was concentrated in the western protected, oil-rich sultanate of Brunei to the north, and the area of what is now Kalimantan, recent Indonesian state of Kalimantan to the south. The coastal activity has focused on the alluvial de- areas of Kalimantan a,re relatively accessible and well posits in the southeast. A progress report on t11e first bulk sample pit in this area known. However, the interior, which comprises approx- found th4t significant amounts of dia- imately two-thirds of the island, is still very remote, and monds appear to be concentrated beneath little has been published on its potentially vast mineral the center of the Dana~lSeran swamp. resources. Yet, along with India, Kalimantan has histori- The traditional hand-mining methods cally been one of the world's oldest sources of fine contrast greatly with the sophisticated diamonds (figure 1). Renewed interest in the diamonds of techniques used to mine the first bulk the area has prompted a great deal of geologic investiga- sample pit. Virtually all of the diamonds tion. The purpose of this article is to review what little is recovered are gem quality, although most known of these remote deposits and to report on recent are relatively small, averaging about 0.30 geologic exploration of, and development activity in, the ct. Future potential for southeastern Kali- Banjarmasin-Martapura area of southeastern Kalimantan mantan appears excellent. (the province of Kalimantan Selatan). The gemological characteristics of diamonds recovered from this area will also be discussed. ABOUT THE AUTHORS In December 1985, Acorn Securities (an Australian Mr. Spencer is a consulting geologist based in In- verell, New South Wales, Australia; Mr. Dikinis is a public company) together with Keymead Pty. Ltd. (a British gemologist and independent importer of dia- private concern) executed a joint exploration and produc- monds and colored stones based in Sonoma, CA; tion agreement with the firm P. T Anelza Tambang (repre- Dr. Keller, a geologist and gemologist, is associ- ate director of the Los Angeles County Museum senting the Indonesian government) to explore for dia- of Natural History, Los Angeles, CA; and Mr. Kane monds in the Banjarmasin-Martapura area of southeastern is senior staff gemologist at the GIA Gem Trade Kalimantan (figure 2). The areas subject to the agreement Laboratory, Inc., Santa Monica, CA. have had a long history of gem-quality diamond produc- Acknowledgments: L. Spencer would like to thank W. W. Shaw. Charles Watson. Acorn Securities, tion. P. T Aneka Tambang, and Keymead Ply., Ltd., During the 1970s) I? T. Anelza Tambang conducted lor their cooperation. S. D. Dikinis wishes to extensive exploration on the fanglomerate gravels (i.e., thank Tom Altgelt, and Chris Johnston for sponsoring his trip; Daum and Vyga Dikinis, Janet those materials that were originally deposited as an Montgomery, Albert Johnston, Cheryl Kremkow, alluvial fan) of the Riam Kanan River, with generally Rosaline Chow, Colin Curtis, Michael Horovitz, and Fillip Freeman for their support; and Mrs. negative results. Little exploration was conducted beneath Helly and Mr. and Mrs. Kuntadi for their guidance. the extensive swamps in the area, however, even though (0 1988 Gemological Institute of America local residents have recovered diamonds for several bun- Diamond Deposits of Borneo GEMS & GEMOLOGY Summer 1988 67 Figure 1. Two recently found crystals (0.76 and 0.68 ct, respectively) flank three older faceted exam- ples of fancy-color diamonds found in Borneo. The three faceted diamonds, 0.20-0.34 ct, were recov- ered from the Cempaka diamond fields early in this century and subsequently faceted in Martaptira. Photo 0 Harold o) Erica Van Pelt. dred years on the flanks and margins of the (960-1279 A.D.). Numerous fragments of Chinese swamps by sinking shafts to the gravel horizon. pottery traced to this period have been found in the Deep water and extensive overburden precluded diamond workings. In the 16th century, the Por- extending the worlzings to the center of these tuguese reached Borneo and noted the workings on swamps. Exploration and development work by the Landalz River. Cutting, probably learned from Acorn in this area has shown that these swamps do India, was done in shops in Ngabang and Pon- indeed contain significant diamond deposits. The tianalz. In the early 17th century, the Dutch information presented here is based largely on a colonized Borneo and began exploiting the dia- geologic exploration progress report on the Banjar- monds through the Dutch East India Company. masin area that was prepared by the senior author Tavernier (1676)reported that in the 17th century, (L. K. Spencer)in October 1987, on the visit of S. D. Borneo paid annual tributes to the Chinese em- Dikinis to Banjarmasin and other areas of Kali- peror and that part of each tribute was in dia- mantan in the summer of 1987, and on geologic monds. research and gemological testing performed by For the most part, early production records l? C. Keller and R. E. Kane. appear to be unreliable. Although several thousand workers were reported in Tanah Laut, near Mar- HISTORY tapura, in 1836, the Dutch government listed a The diamond deposits of Borneo are believed to total diamond production of only 29,857 ct be- share with India the distinction of being the tween 1836 and 1843 (Bauer, 1904). These figures earliest worked diamond mines in the world (see do not differ significantly, however, from the box), although researchers have not been able to 25,378 ct estimated by merchants at Ngabang for pinpoint the exact date that mining began. For production between 1876 and 1880. Bauer reported example, Webster (1983)believes that mining may that "in 1880 the mines on the Sekayam River were have started on the island as early as 600 A.D., and worked by about 40 Chinese only, those in Landalz that mining was certainly carried out since the gave employment to about 350 workers." With the 14th century. Bruton (1978)does not believe that discovery of diamonds in South Africa in the late mining in Borneo started until the 16th century. 19th century, Borneo's diamond production be- Schubnel (1980), however, provides strong evi- came insignificant. Whereas an estimated 6,673 ct dence that the area on the Sungai Landalz (Landalz of diamonds were produced in western Kaliman- River) in western Kalimantan was worked by the tan in 1879, that number dropped steadily to only Malays and Chinese as early as the Sung period 600 ct in 1907 and minor amounts subsequently. 68 Diamond Deposits of Borneo GEMS & GEMOLOGY Summer 1988 During the period 19 13-1 936, diamond production Beminelen, 1939). Today, production in western in southeastern Kalimantan fluctuated between Kalimantan is minimal, and mining activity and 236 and 2,152 ct, but started a significant upward exploration are concentrated in the southeast, near rise from 907 ct in 1937 to 3,292 ct in 1939 (Van Banjarmasin and Martapura. 1 Figure 2. This map shows the two major areas (left = the Landak district of western Kali- man tan, below = the Bmjarn~asin-Maitapura area of southeastern Kalimantan) where din- monds have been found in the Indonesian state of Kalimantan, on the island of Borneo. Artwork by fan Newell. Diamond Deposits of Borneo GEMS &. GEMOLOGY Summer 1988 69 A Brief History of Diamond Mining in Ka1imantan.a Hindus are probably the first to discover been quartz) is reportedly found in the area diamonds (Webster, 1983). of the Landak River. The Malays vanquish the Hindus and initi- 1780- The Dutch East India Company experiences ate the first diamond mining. 1800 a decline in its trade monopoly and diamond Chinese miners work the Landalz area for mining. gold and diamonds (Schubnel, 1980). 1810- Stamford Raffles, governor of Java, writes an Duarte Barbosa, of Portugal, provides the 1830 extensive history of the diamond fields. first written reference to diamond mining in 1823 Englishman George Windsor Earl reports Borneo. the Dutch purchase of the Sukadana dia- Feran Mindez Pinto, of Portugal, provides mond fields for the equivalent of US$50,000. the first description of diamond mining. 1828 Earl reports the blockading of Pontianak by Garcias ab Horto, of Portugal (Goal, provides Dutch gunboats to stop diamond smuggling the first description of the quality, shape, by the Chinese. and other characteristics of Borneo dia- 1842 Chinese miners are massacred at Landak. monds. 1880s- The discovery of major diamond deposits in De Moraga, of Spain (Philippines),mentions South Africa leads to the decline of the the first Portuguese trading in diamonds. Borneo diamond fields. Captains Middleton and Sare are the first The Dutch undertake mining at Cempaka, Englishmen to describe the diamond mines. and attempt to trace the source of the The first Dutch trading posts are set up at alluvial diamonds. Pontianak. Production (unrecorded)continues after the Jean Baptiste Tavernier provides the first Japanese invasion. Many Japanese vessels detailed description of diamonds and of carry gems during the occupation, The cargo flourishing trade at Batavia (now Jakarta). carried by the cruiser Ashigara when it was The Dutch East India Company exercises a sunk off the coast of Sumatra is valued at full monopoly on diamond trading from £4,000,000 Borneo. The Netherlands transfers sovereignty to an Late The Martapura diamond field is discovered.