This obscure rare earth metal polishes well AND keeps its luster in open air so long as you don’t get it wet (in which case it will leave a hazy stain). Placed next to a gray color reference, gadolinium appears to have a very slight yellow color.

Gadolinium is also the unlikely focus of a controversy within the medical world. It turns out that it’s especially effective in MRI scans. As the acronym hints at, MRIs do their magic by exploiting small differences in magnetic fields within the body. These differences can be mapped and then formed into an image which can then be used in diagnosing many kinds of diseases.

Gadolinium’s role in these machines functions as a contrast enhancer to make those images clearer. While the iron in blood is magnetic it’s literally everywhere in the body so it’s no use for this task. What’s needed is a material that is magnetic but only just enough of it, like a fine dusting, to reveal hidden outlines. Gadolinium, which is slightly magnetic, is an exotic material that has no natural reason to accumulate in tissues. When the patient drinks a mix containing a small quantity of gadolinium these particles disperse via the bloodstream and their unique signature can be picked up by the scanner delineating more clearly the boundaries of organs and whatever other tissues are being examined.

The controversy stems from what-if questions arising out of potential litigation. Being a substance normally alien to the human body - and even though apparently harmless in the small quantities used - trace amounts of Gd may continue lingering in the body long after the MRI scan served its purpose…. and potentially be used in litigation should the patient sprout a condition whose origins can’t be explained otherwise. Fear of malpractice lawsuits is therefore putting pressure on engineering workarounds to phase out the use of this metal.

But don’t feel too bad for the underdog. The demand for gadolinium in the medical industry is truly a drop in the bucket compared to its much larger market in the electronics and auto industries. Just don’t forget to take your gadolinium cube out of your pockets when you show up for your next MRI ;-)