They also located a diamond pipe just below the surface in the major rift valley fault.

In general, the material in the diamond pipes is from depths far greater than any other known volcanic rock.

The tops of many diamond pipes are craters rather than cones.

For reasons that elude modern science, diamond pipes are found exclusively in ancient areas of the continents known as cratons, which are generally more than 1.5 billion years old.

So far more than 100 diamond pipes have been found in the Northwest Territories and the quality of the ore appears to be good.

All the other great diamond pipes, from Kimberly to Wesselton, were pegged by hundreds of individual miners, and each started working independently of his neighbour's efforts.

This world's economy must collapse; that lone miner must discover his planet's only diamond pipe.

"Because there's a diamond pipe about five miles from Ophir."

"What's a diamond pipe?"

He dug from dawn until dusk, looking for the yellow clay or the blue diamondiferous soil that would tell him he had found a diamond pipe.