General Electric synthetic diamond development (Tracy Hall)

Aside to explain why diamond appears on Westbrook's structural-materials plot — GE had a near-monopoly on synthetic diamonds at the time of the 1962 plot.

Here's stone — the most highly used material in the world, and it has been for millennia. Here's cement, here's carbon steel, and he's got alloy steel down here used at about one-tenth the volume. These are large numbers — 10 to the 11th pounds per year. That's a lot of material. These are also market size — this was a billion-dollar market in 1962, a hundred-billion-dollar market today. Out at the end, diamond is a structural material. You may not build buildings out of it, but it's a structural material — you're using it for mechanical properties or its optical properties. People use it for optical fronts, and as a structural material it has important uses. Remember, this is a General Electric report, and at the time General Electric had a near monopoly on man-made diamonds, because of Tracy Hall among other people who'd invented the process to make man-made diamonds. Cemented carbides are structural materials, just like diamond. About a hundred dollars a pound. Diamond back then was ten thousand dollars a pound. It's about four hundred million dollars a pound now or something like that. Ashby's got some updated prices.