The diamond washings of the Mahanadi, a little above Sumbulpore, are exclusively from alluvial diggings ; but the fact that they occur just outside and below the great lower Vindbyan basin, has suggested the conjecture that the gems are derived from those rocks, on the ground that these are the equivalents of the diamond-bearing beds of Southern India. The Joorah, who are fishermen by caste, are the diamond searchers of the Mahanadi, at a place called Heeracode, near Chanderpore, adjacent to the place where the river Mand joins the Mahanadi. The river here makes a sudden turn to the left, where, amongst the smaller streams, which thoy dam up for a, time, the diamonds are searched for during the hot season, generally commencing at the termination of the monsoon. The men throw tbe sand on the bank, and the women wash and ex pose it to the sun and select the diamonds.
In the main Vindhyan basin, diamonds are only known to occm. in the Upper Vindhyans. Here, as everywhere, the great majority of the diggings are alluvial, but the principal workings are in a bed at the very base of the Rewa shales. Not withstanding the immense range of this group, it is only known to be productive within a small area of the Panna State, on the borders of the Bundel khand gneiss, and the surface diggings are con fined to the same neighbourhood. Here, as in the Banaganapilly mines, the diamond-layer is con glomeratic.
A notice of the Pannah mines is in Dalrymple's Indian Repertory (ii. p. 471), and there de scribed as on a range of hills situated about 42 coss S.S.W. of Kalpi. The bills are called by the natives Band Achil ; they extend about 12 coss in length and about 2 or 3 in breadth, and are divided into 21 districts, of which only the following nineteen names are given :— Pirnah, Gurriah, Anwont Pokennu, Channu, Birdu, Kalil anpur, Pullu, Raipur, Eta,wa, Maharajpur, Raj pur, Kimmerah, Gadahsiah, Ranpur, Cherriapuri, Attupurah, Merah, Singupurah, and Mujiouah. Diamonds are found in all these districts°, but those of Maharajpur, Rajpur, Kimmerah, and Gadahsiah are the largest and best.
In the Bundelkhand area, a, cberty contact rock' coats the gneiss under the Kaimur sandstone ; and in Chattarkot hill the contact rock occurs under the limestone, holding its position as a true bottom rock. It has been conjectured that this peculiar contact rock may possibly be an original nidus of the diamond. A common form of it is a semi vitreous sandstone. Large pebbles of it are very abundant in the conglomerate diamond bed of the Rewa shales at the Panna mines, and are said to be broken up in the search for diamonds. The search for diamonds in Panna is not, how ever, confined to positions in which the gems could be derived from any existing outcrop of the Rewa shales. There are numerous pits of surface diggings
in the gorges and on the slope of the Upper Rewa, sandstone, south of Panna.
The Chinese Shan-tung diamonds are mostly very minute, varying in size from a millet seed to a, pin's head, though occasionally larger ones are met with. Men with thick straw shoes on, walk about in the sands of the valleys and streams of the dia mond mountains of Chin-kan..-ling, Borne 15 miles ' S.E. of Yi-chow-foo. The s°hoes are burnt, the diamonds being searched for in the ashes. As in the case with amethysts and rock-crystal in the Lao-shau, the priests in the temples in the Chin kang-ling are the principal dealers in these small diamonds. From them they are bought by glaziers at the large fairs held every year at Chu-chow, Lai-chow-foo, and Hwang-hsien.
The diamond has been found in'Borneo, in the district of Landak, in the territory of Pontianak, in long. 109° E., about 40 miles N. of the equator, and they occur from thence as far as Banjarmasin, between long. 114° and 115° E. The mines are worked by the Dyak, Malay, and Chinese. The gems are found in a yellow-coloured rubble or gravel, which occurs at various depths, the great est to which a shaft has been known to be sunk being between 50 and 60 feet. Six different alluvial strata occur before reaching the diamond yielding one, which tbe Malays call the aren... These strata are, a black mould, a yellow sandl clay, a red clay, a blue clay, a blue clay inter mixed with gravel, called by the Malays ampir, or near at hand, and lastly a stiff yellow clv, which the diamonds are embedded. The prince of Matan has a rough diamond of 367 carats, but its 'genuineness has been suspected. It was found in 1787 at Landak. • The first South African diamond was found in 1867. A little girl was playing with it on the floor of a house in Albania, Griqualand West. Soon afterwards the Star of South Africa, weigh ing 83 carats, was found. :The Porten-Rhodes diamond was found in the Kimberley mine, 12th February 1880. It weighed 150 carats uncut, and £60,000 had been offered for it. Kimberley naine is the richest there. It has an area of about 7 acres, and its first owner sold it for £6000 ; but in 1880 it was yielding £20,000 to 125,000 in rents, for about 400 claims. • After the Star of the South of Africa, a diamond was found in 1872 -which weighed 288i carats. In 1880 the gross weight of packages passed through the Kimberley post office was 1440 lbs. 12 oz. avoirdupois, the esthnated valuebeing £336,897. At the end of the year, 22,000 blacks and 1700 white men were employed in the Kimberley divi sion mines.