Alluvial Diamonds: Out of the 13,677 islands of Indonesia, the island of Kalimantan, the third largest in the world, is known for diamonds. Alluvial diamonds have been recovered in this area since the last two centuries, but systematic exploitation has never been attempted. Geological investigations earlier in the last century proved the widespread presence of diamonds. It is believed that the Kanan river and its tributaries were the principal downstream carriers of diamonds. Wholesale labrorite Jewellery
Subsequently in 1953 came the discovery of diamond bearing ultra-basic rock at Pamali. Uniquely, this rock carried gold as well as diamonds. A secondary source area appears to have been located near the Gunung Bukit Besar locality which shed diamonds into rivers flowing both westwards and eastwards. But till date the mystery of the primary source of Kalimantan diamonds remains unsolved. Wholesale moonstone Jewellery

Wide River-borne Dispersal : Deposits have been scattered as a result of the dispersal along numerous rivers flowing seaward from the interior, transporting them from diamondiferrous pipes. Today those pipes have either been eroded away or are yet to be found in the vast tropical, swampy jungles of the interior. Thus in Indonesia the richest diamond concentrates are, contrary to usual rule, found far away from their presumed original source. The diamonds are well crystallized with octahedrons predominant and frequently with rounded edges.
Search for more diamonds and their sources is very difficult in the Kalimantan as only some areas can be reached by road or navigable rivers. The rest is forbidding primitive territory. Local villagers are reported to be digging for diamonds illegally. Their total production could be as high as 50,000 cts or even more per annum, it was conceded officially, but regulatory measures are yet to be taken. Wholesale turquoise Jewellery
Alluvial production in Kalimantan is estimated at 15,000 to 30,000 carats per year from small-scale operations.

An authorized project for gathering alluvial diamonds was launched by an Australia-based company that conducted an operation in the south-east Kalimantan region.

Production & Polishing: The Indonesian Diamond Corporation signed formal documents for the project at Danau Seran in South East Kalimantan to go ahead. The Danau Seran Channel mine area, which contains diamondiferrous gravel at a grade of 0.1 carat per cubic metre, was scheduled to be mined by the 'dry mining' method (open pit mining in a wetland).
Diamond Processing: Indonesia has some small diamond processing factories, but diamond processing is still far from modernization.
An Indian diamond cutting centre was set up at Sungai Pareng, Martapura. It has been sponsored by the Bank of Indonesia. Workers ofthe centre were trained in Netherlands. It is estimated that of around 180,000-200,000 carat roughs used by the Indonesian diamond polishing industry, only 15 per cent inflow is from local sources.