A fair amount of Earth science research is based on incredibly subtle measurements of isotopes obtained from minerals or the remains of long-dead organisms. Surprising histories and insights can be recorded in minute shifts of these isotopes. But we never talk about how those measurements are made, since this particular sorcery is commonplace in modern science.
For example, a recent story about how quickly Yellowstone has coughed up eruptions in the past stated, The researchers made spot measurements tiny spots less than half a micron apart of barium, strontium, and magnesium crossing the boundary of the [feldspar] crystal rims. Hidden behind that sentence is some remarkable technology and many hours spent using it. (That's what happens when you reduce several years of 21st century research to 800 words.)
To make partial amends for this slight, Ars visited a lab in the University of Wisconsin-Madison's geoscience department to check out one of the instruments behind this magic. That lab is managed by John Valley and Noriko Kita and is kept running through the hard work of several others. Like other geologists, Valley used to interrogate tiny crystals of the mineral zircon the only way he could by tossing a pile of them into an instrument and making bulk measurements of their chemistry. If those crystals were uniform, with no difference between or within them, that would be great. But there was no way to know whether this was true.