Six valuable rare eaths, shown in powdered oxide form. Neodymium, a key component of electronic devices, is at front.

Courtesy Peggy Greb/USDA

In Ytterby there are two secret pasts. Two centuries ago, the sleepy village—now dotted with vacation homes belonging to wealthy residents of nearby Stockholm—was a restless mining settlement, shipping out high-grade feldspar for the royal porcelain factories of Europe and quartz to line the blast furnaces springing up across England. It is also the birthplace of some of nature’s most wondrous and least appreciated chemical elements.

The latter story began in 1787, when an amateur geologist named Carl Arrhenius was visiting a mine in Ytterby. He discovered an unusually heavy black rock among the gray outcroppings and, being a man of healthy scientific curiosity, sent a sample for analysis to Johan Gadolin, a prominent chemist at the Royal Academy of Turku in Finland. In 1794 Gadolin concluded that the specimen contained an entirely new element, later named yttrium. By 1879 chemists had isolated six additional elements from the same rock, bringing the grand total in the newly invented periodic table to 70. Three of those elements—ytterbium, erbium, and terbium—were simply given additional variants on the name of Ytterby, while the other three were named holmium (for Stockholm), scandium, and thulium (both from the Latin for Scandinavia), in the nationalistic fashion then in favor. After a long, lucrative run, the Ytterby quarry was closed in 1933. In many ways, though, the town’s influence looms larger than ever. The elements discovered there, known collectively as rare earths, today form the backbone of the modern wired and wireless world—even though you have probably never heard of them.

The name rare earths made sense to the 19th-century mind: rare because it seemed at first that they came only from Scandinavia, and earths because they occurred in an earthy oxide form from which it was exceptionally hard to obtain the pure metal.


Today it is clear that the rare earths are hardly rare. The most common of them, cerium, ranks 25th in abundance in the earth’s crust, one place ahead of homely copper. Yttrium is twice as abundant as lead; all of the rare-earth metals (with the exception of radioactive promethium) are more common than silver. The “earths” part is also misleading. These elements are actually metals, and quite marvelous ones at that. The warm glow of terbium is essential to high-efficiency compact-fluorescent bulbs. Europium is widely exploited to make vivid displays for laptop computers and smart phones. Rare earths also pop up in more unexpected places like baseball bats, European currency, and night-vision goggles.

With their growing popularity comes new value, and even political notoriety. Terbium and europium recently overtook silver in price, reaching $40 an ounce. The growing demand for rare earths has become the subject of numerous government reports and a bill that passed in the House of Representatives. The reason these elements are causing such a stir is not their scarcity but their inaccessibility. Rare earths tend to occur in hard rock such as granites, where they lump together in a uniform way that makes them difficult to extract.

Separating out the desired elements demands a toxic and dangerous process, and China has the best infrastructure for doing so economically. China holds about 36 percent of the world’s 110 million tons of recoverable rare-earth ores, with the rest scattered worldwide, principally in the United States, India, Australia, and Russia. Yet China currently produces as much as 97 percent of the world’s rare-earth oxides, according to the U.S. Government Accountability Office. Pekka Pyykkö, a professor of chemistry at the University of Helsinki, puts it this way: “Not all the deposits are in China, but the processing capacity right now is.”

Supply would not matter if not for demand, and the demand comes from the unusual electrical properties of the rare earths—or lanthanides, as chemists prefer to call them, because they mostly follow lanthanum in the periodic table of elements. The lanthanides share similar chemical properties because they all react similarly, mostly with their three outer electrons. (An atom’s arrangement of electrons is what determines most of its physical and chemical attributes.) Like copper, iron, cobalt, and other more familiar metals, lanthanides form many colored compounds. The magic happens when those outer electrons change energy states and release visible light. But the rare earths are especially valuable for their property of fluorescence: They can absorb light or ultraviolet rays and re-emit the energy as an eerie glow of certain colors specific to each element. The brilliant emission of red and green is the reason why lanthanides are indispensable components of today’s television sets and compact fluorescent bulbs.

From a technological perspective, a more intriguing trait of the rare earths is that some of them are highly magnetic. Alloyed with other metals, they make extraordinarily strong and compact magnets: perfect for computer hard drives, cordless power tools, microphones, and headphones. An iPod takes a triple sip of rare earths: to store digital music, to re-create it in earbuds, and to display what is playing. An iron alloy containing terbium and dysprosium has a particularly useful property: It expands and contracts efficiently in the presence of a magnetic field. Sensors, actuators, and injectors commonly use such materials, for instance to regulate the flow of gasoline into an automotive engine.