Translation guide
In English, "rare earth" refers to a group of chemically similar metallic elements (the rare earth elements) or their oxides. In Japanese, the term is usually translated directly, but there are important distinctions between the elements themselves and their compounds.
rare earth (elements)
Most common term in general contexts.
rare earth (technical/scientific)
Used in academic or industrial settings.
Referring to the set of 17 metallic elements including the lanthanides plus scandium and yttrium.
The most common term, borrowed from English. Used in news, industry, and everyday conversation.
Rare earths are essential for high-tech products.
The native Japanese term, often used in scientific or technical contexts. Literally 'rare earth group'.
Rare earth elements belong to the lanthanides in the periodic table.
Explicitly 'rare earth elements'. Used in chemistry and materials science.
Rare earth elements have similar chemical properties.
Referring to the naturally occurring compounds or the oxides extracted from them.
レアアース is the everyday loanword, while 希土類 is the native technical term. In news media, レアアース dominates. In scientific papers, 希土類 is more common. Both refer to the same group of elements.
Imports of rare earths are increasing.
Separation technology for rare earths has advanced.
Do not translate 'rare earth' literally as 珍しい土 (めずらしいつち). That means 'unusual soil' and is incorrect. The term refers to specific metallic elements, not dirt.
China is the largest producer of rare earths.
Rare earth magnets are used in electric vehicles.
Rare earth oxides are raw materials for magnets.