Titanium

William Gregor found it in Cornish black sand in 1791 and Klaproth named it after the Titans, but titanium stayed a laboratory curiosity until William Kroll worked out in 1940 how to reduce the tetrachloride with molten magnesium. The Kroll process is a batch operation that takes days, which is the whole reason titanium costs what it does. Its most famous application is also its most awkward: the SR-71 Blackbird was over 90% titanium, and in the early 1960s the only adequate supply was the Soviet Union, so the CIA bought it through a web of front companies and third countries. Titanium bonds to bone well enough that dental implants osseointegrate. Yet about 95% of all titanium ore never becomes metal at all — it becomes titanium dioxide, the brilliant white pigment in paint, paper, toothpaste and sunscreen.