The Yield of Diamonds
Sometimes as many as 8000 carats of diamonds come from the pulsator in one day, representing about £20,000 in value.
When the bare statement is made that nearly 5,000,000 truck-loads, or more than 4,000,000 tons of blue ground, have been washed in a year, the mind only faintly conceives the prodigious size of the mass that is annually drawn from the old craters and laboriously washed and sorted for the sake of a few bucketfuls of diamonds. It would form a cube of more than 430 feet, or a block larger than any cathedral in the world, and overtopping the spire of St. Paul’s, while a box with sides measuring 2 feet 9 inches would hold the gems. From two to three million carats of diamonds are turned out of the De Beers mines in a year, and as 5,000,000 carats go to the ton, this represents half a ton of diamonds. To the end of 1892 10 tons of diamonds had come from this mine, valued at £60,000,000 sterling. This mass of blazing diamonds could be accommodated in a box 5 feet square and 6 feet high.
The diamond is a luxury, and there is only a limited demand for it throughout the world. From four to four and a half millions sterling is as much as is spent annually in diamonds; if the production is not regulated by the demand, there will be over-production, and the trade will suffer. By regulating the output the directors have succeeded in maintaining prices since the consolidation in 1888.
The blue ground varies in its yield of diamonds in different mines, but is pretty constant in the same mine. In 1890 the yield per load of blue ground was:
| CARATS | |
| From the Kimberley Mine | from 1·25 to 1·5 |
| ” De Beers Mine | ” 1·20 ” 1·3 |
| ” Dutoitspan Mine | ” 0·17 ” 0·5 |
| ” Bultfontein Mine | ” 0·5 ” 0·33 |
Varieties of Diamonds
Fancy Stones
Diamonds occur in all shades, from deep yellow to pure white and jet black, from deep brown to light cinnamon, also green, blue, pink, yellow, orange, and opaque.
Both in Kimberley and De Beers the blue ground on the west side is poorer in diamonds than the blue ground in other parts of the mines. The diamonds from the west side also differ somewhat from those in other parts of the same mine.