No, it is not something bad, like dysfunctional or dyslexia. It is not a medicine either. A few of us, barring chemistry freaks, may know this from the Periodic Table of Elements, part of a group called Lanthanides. It is an element, like Iron, or Copper. Except that the world manufactures (from natural ores) only about 100 tonnes per annum of this substance. So it is rarer than gold, literally speaking. But strangely, currently worth much less than its weight in gold, at close to $2,500 per kg. Gold is many, many times costlier. So what?
China makes 99 tonnes out of that 100 tonnes. So what? China has restricted its export, along with a clutch of similar improbably named elements collectively called as rare earth metals. China has only 12 years' worth of output (estimated) left in the clay mines that are the source of the ore. Naturally, China wants to conserve its reserves for its own use, and have clamped export limits. The United States, as always, wants China to ease these export restrictions, going to the extent of filing a WTO complaint against China.
Strangely, China has 35% of world reserves but accounts for 97% of current world production of rare earth metal oxides! And guess what, USA has significant rare earth reserves (1/3rd of China's according to the figures put out by the US Geological Survey's Mineral Commodity Summaries, January 2010 ) that it is currently not exploiting at all. Indeed, the report notes that “Bastnäsite deposits in China and the United States constitute the largest percentage of the world’s rare-earth economic resources ”. Molycorp Minerals, a mining company, is even as I write this, engaged in a fight with the US Government to get one of its mines re-opened, lying closed since 2002. Australia and the CIS countries also have significant reserves that are currently almost not utilised at all. Why so? The answer may lie in the genesis of the name: Dysprosium is derived from the Greek “dysprositos” that means hard-to-get-at!
Toyota requires 100 grammes per car of this substance to make the drive motors for its hybrid car, Prius. The entire world's current output would be sufficient for only a million hybrid cars. But then, they are not the only guys vying for the substance.
It is used in almost all mobile phones, flat screen TVs and computer monitors, nuclear reactor fuel rods, magnetomechanical sensors, actuators, automotive catalytic converters, high-precision liquid fuel injectors and acoustic and ultrasonic transducers (don't worry about what some of these things are or do – suffice it to say that they generate demand for Dysprosium). Wind power generators require it, as do hard disks. High-intensity commercial lighting and lasers use an alloy including this.
Can we manufacture it synthetically? Not yet! So the world has no alternative to focus on commercializing the existing reserves, and ore-processing capacity.
What if the world runs out of Dysprosium? We can still make do, but any substitutes will most likely be heavier and more inefficient with respect to magnetic properties. So no more sleek iPhones, tablets, netbooks. Non-renewable (nuclear, wind) energy will become costlier. No Prius. Unless we learn to make it synthetically, or find much more efficient magnets not using Dysprosium.