The name Cecil John Rhodes is so intrinsically linked to the diamond industry that it's a little known fact that by the time Rhodes actually got to Kimberly in 1871, there were already around 50,000 people there. How did he, out of those 50,000 people, emerge to be the chairman of De Beers, still the world's largest diamond company?

The short answer is, it didn't happen overnight; he was deft and creative and an extraordinary mover and shaker. He was also helped by his ice machine. He and his partner Charles Rudd bought an ice machine in London, brought it to Kimberly and sold ice to the miners. They did a roaring trade because Kimberly is searingly hot at the best of times.

How much of a difference the ice machine made in Rhodes' ability to buy up all the rival claims at Kimberly is not clear, but it falls into the category of the "picks and shovels" theory of business.

This theory is that the big money seldom derives from the most obvious source, in this case, diamonds. At the original gold diggings in the US, for example, the people who made the most money were not the gold...