Mickey Fulp: Well, I'm not sure what investors should be concerned with, but the rare earth elements are very well defined: Elements number 57 through 71 on the periodic table—the elements located along the next-to-the-bottom row. They all end in -um or -ium: From lanthanum to lutetium. That's 15 metals, plus yttrium, which is above lanthanum on the periodic table and is included because it is the most abundant one that occurs with the heavy REEs. The light REEs are generally defined as the first five along the periodic table but one of those, promethium, does not occur in nature.
There is a lot of confusion among lay investors. And there's confusion even among some of the so-called experts about the "critical metals" sector. Last year they were called technology or rare metals; the year before they were called strategic metals. Historically, these metals have been called specialty metals or minor metals for a variety of reasons. They generally don't occur in standalone mines; they are often byproducts of mining or smelting; they don't trade on the world market; they have special, niche, and/or minor uses. Sometimes they are lumped all together as one.
In my opinion, "critical metals" are the ones that are a necessity for the world to function—elements like iron, copper, aluminum and nickel. I would prefer to call all the others what they have been called for many years: Minor metals or specialty metals. They would include lithium, beryllium, zirconium, niobium, tantalum, indium and the REEs. Are they critical? No. Are they essential? No, but that said, they have special uses that make our lives easier and more diversified. For instance, if it weren't for REEs, we'd all be carrying around Gordon Gekko-sized cell phones.