Visualizing the Abundance of Elements in the Earth’s Crust

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Elements in the Earth’s crust provide all the basic building blocks for mankind.

But even though the crust is the source of everything we find, mine, refine, and build, it really is just scratching the surface of our planet.

After all, the innermost layer of the Earth, the core, represents 15% of the planet’s volume, whereas the mantle occupies 84%. Representing the remaining 1% is the crust, a thin layer that ranges in depth from approximately 5-70 km (~3-44 miles).

This infographic takes a look at what elements make up this 1%, based on data from WorldAtlas.

Earth’s Crust Elements

The crust is a rigid surface containing both the oceans and landmasses. Most elements are found in only trace amounts within the Earth’s crust, but several are abundant.

The Earth’s crust comprises about 95% igneous and metamorphic rocks, 4% shale, 0.75% sandstone, and 0.25% limestone.

Oxygen, silicon, aluminum, and iron account for 88.1% of the mass of the Earth’s crust, while another 90 elements make up the remaining 11.9%.

While gold, silver, copper and other base and precious metals are among the most sought after elements, together they make up less than 0.03% of the Earth’s crust by mass.

#1: Oxygen

Oxygen is by far the most abundant element in the Earth’s crust, making up 46% of mass—coming up just short of half of the total.

Oxygen is a highly reactive element that combines with other elements, forming oxides. Some examples of common oxides are minerals such as granite and quartz (oxides of silicon), rust (oxides of iron), and limestone (oxide of calcium and carbon).

#2: Silicon

More than 90% of the Earth’s crust is composed of silicate minerals, making silicon the second most abundant element in the Earth’s crust.

Silicon links up with oxygen to form the most common minerals on Earth. For example, in most places, sand primarily consists of silica (silicon dioxide) usually in the form of quartz. Silicon is an essential semiconductor, used in manufacturing electronics and computer chips.

#3: Aluminum

Aluminum is the third most common element in the Earth’s crust.

Because of its strong affinity for oxygen, aluminum is rarely found in its elemental state. Aluminum oxide (Al2O3), aluminum hydroxide (Al(OH)3) and potassium aluminum sulphate (KAl(SO4)2) are common aluminum compounds.

Aluminum and aluminum alloys have a variety of uses, from kitchen foil to rocket manufacturing.

#4: Iron

The fourth most common element in the Earth’s crust is iron, accounting for over 5% of the mass of the Earth’s crust.

Iron is obtained chiefly from the minerals hematite and magnetite. Of all the metals we mine, over 90% is iron, mainly to make steel, an alloy of carbon and iron. Iron is also an essential nutrient in the human body.

#5: Calcium

Calcium makes up about 4.2% of the planet’s crust by weight.

In its pure elemental state, calcium is a soft, silvery-white alkaline earth metal. It is never found in its isolated state in nature but exists instead in compounds. Calcium compounds can be found in a variety of minerals, including limestone (calcium carbonate), gypsum (calcium sulphate) and fluorite (calcium fluoride).

Calcium compounds are widely used in the food and pharmaceutical industries for supplementation. They are also used as bleaches in the paper industry, as components in cement and electrical insulators, and in manufacturing soaps.

Digging the Earth’s Crust

Despite Jules Verne’s novel, no one has ever journeyed to the center of Earth.

In fact, the deepest hole ever dug by humanity reaches approximately 12 km (7.5 miles) below the Earth’s surface, about one-third of the way to the Earth’s mantle. This incredible depth took about 20 years to reach.

Although mankind is constantly making new discoveries and reaching for the stars, there is still a lot to explore about the Earth we stand on.

Rare Earths Elements: Where in the World Are They?

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Rare earth elements are a group of metals that are critical ingredients for a greener economy, and the location of the reserves for mining are increasingly important and valuable.

This infographic features data from the United States Geological Society (USGS) which reveals the countries with the largest known reserves of rare earth elements (REEs).

What are Rare Earth Metals?

REEs, also called rare earth metals or rare earth oxides, or lanthanides, are a set of 17 silvery-white soft heavy metals.

The 17 rare earth elements are: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), scandium (Sc), and yttrium (Y).

Scandium and yttrium are not part of the lanthanide family, but end users include them because they occur in the same mineral deposits as the lanthanides and have similar chemical properties.

The term “rare earth” is a misnomer as rare earth metals are actually abundant in the Earth’s crust. However, they are rarely found in large, concentrated deposits on their own, but rather among other elements instead.

Rare Earth Elements, How Do They Work?

Most rare earth elements find their uses as catalysts and magnets in traditional and low-carbon technologies. Other important uses of rare earth elements are in the production of special metal alloys, glass, and high-performance electronics.

Alloys of neodymium (Nd) and samarium (Sm) can be used to create strong magnets that withstand high temperatures, making them ideal for a wide variety of mission critical electronics and defense applications.

The strongest known magnet is an alloy of neodymium with iron and boron. Adding other REEs such as dysprosium and praseodymium can change the performance and properties of magnets.

Hybrid and electric vehicle engines, generators in wind turbines, hard disks, portable electronics and cell phones require these magnets and elements. This role in technology makes their mining and refinement a point of concern for many nations.

For example, one megawatt of wind energy capacity requires 171 kg of rare earths, a single U.S. F-35 fighter jet requires about 427 kg of rare earths, and a Virginia-class nuclear submarine uses nearly 4.2 tonnes.

Global Reserves of Rare Earth Minerals

China tops the list for mine production and reserves of rare earth elements, with 44 million tons in reserves and 140,000 tons of annual mine production.

While Vietnam and Brazil have the second and third most reserves of rare earth metals with 22 million tons in reserves and 21 million tons, respectively, their mine production is among the lowest of all the countries at only 1,000 tons per year each.

While the United States has 1.5 million tons in reserves, it is largely dependent on imports from China for refined rare earths.

Ensuring a Global Supply

In the rare earth industry, China’s dominance has been no accident. Years of research and industrial policy helped the nation develop a superior position in the market, and now the country has the ability to control production and the global availability of these valuable metals.

This tight control of the supply of these important metals has the world searching for their own supplies. With the start of mining operations in other countries, China’s share of global production has fallen from 92% in 2010 to 58%< in 2020. However, China has a strong foothold in the supply chain and produced 85% of the world’s refined rare earths in 2020.

China awards production quotas to only six state-run companies:

• China Minmetals Rare Earth Co
• Chinalco Rare Earth & Metals Co
• Guangdong Rising Nonferrous
• China Northern Rare Earth Group
• China Southern Rare Earth Group
• Xiamen Tungsten

As the demand for REEs increases, the world will need tap these reserves. This graphic could provide clues as to the next source of rare earth elements.