Method

The same questions for every element

We answer the same questions for every element, in the same order, so you can compare two elements chapter by chapter. When we have no answer to a question for an element, we say so and give the reason.

Chapter	Questions
How much there is	In nature · Reserves and resources · Is it running out?
Where it is found	Minerals and ores · How deposits form · Where the deposits are · What it comes with
How we get it	How much is produced · Who produces it · How it is mined and refined · What it costs to produce · Recycling
What we use it for	Where it goes · Why this element · What could replace it · Where demand is going
What it costs	Price · Price history · How it is traded
Who controls it	How concentrated supply is · Who depends on it · How governments treat it
Social and political problems	Conflict and disputes · Workers and communities · Who gains and who loses · Public debate
Harm to health and the planet	Environmental footprint · Health and the body
History	Discovery and name · How our use changed

Where the numbers come from

We give the source of every number and the year that the number is for. We use sources in this order of preference:

1. Official statistics: the US Geological Survey, the British Geological Survey, the International Energy Agency and national agencies.
2. Peer-reviewed papers.
3. Industry associations, for their own industry.
4. Reference works.
5. News reports, for events only.

We cite a source only after we read it. We do not use a source that is behind a paywall or a login. When two good sources disagree, we give both and the reason for the difference.

How a chapter is checked

A chapter goes through three readings, each by a different reader:

1. Draft. A writer reads the sources and writes the chapter and the data.
2. Checked. A second reader opens every source and checks every citation against it.
3. Audited. A third reader checks every claim against current research and other sources.

We put the date of the last update on each chapter page.

Reserves and resources

A resource is a concentration of a material in or on the Earth's crust. It is possible to extract it now, or it can become possible in the future. Reserves are the part that could be extracted at a profit when the estimate was made.¹ Reserves grow when prices rise, when technology improves and when companies explore. Reserves divided by a year's production is therefore not the number of years until an element runs out.

Abundance

Abundance is given in parts per million by mass (ppm): grams of the element in a tonne of rock, seawater or body. One ppm is 0.0001%. Gases in air are given in parts per million by volume.

How concentrated supply is

The Herfindahl-Hirschman index (HHI) is the sum of the squared percentage shares of all suppliers. With one supplier, the HHI is 10,000. In the US merger guidelines, a market with an HHI above 1,800 is highly concentrated. In older guidelines, 1,000 to 1,800 was moderately concentrated.² Those guidelines are about companies. We apply the same arithmetic to countries, because countries can restrict exports. We compute the HHI from the country table on the page. We leave out the countries that are grouped together as "other" in the source, so the true HHI can be a little higher.

Prices

Elements are sold in different forms: ore, concentrate, metal of a given purity, compressed gas. For each price, we give the form, the place and the date. Prices of different elements are therefore only roughly comparable.

Who does the work

AI models do the research and the writing, under the direction of the site's owner. The owner decides what the site covers and how it looks. For every claim, we give a source that you can check. If you find a mistake, we record the fix in the changelog.