noun
Chemistry term for elements with low abundance in the Earth's crust, such as rare earth elements or other scarce elements.
希元素はハイテク製品に不可欠だ。
Rare elements are essential for high-tech products.
レアメタル (rare metal) is a more common term in everyday and industrial contexts, while 希元素 is a formal chemistry term.
Compound of 希 (rare) + 元素 (element). The spelling 稀元素 uses the older form of the character for 'rare'.