What is a major element in mineralogy ?

Major element : definition

In mineralogy, this term designates a constituent element essential for the formation of a mineral. A major element is usually present in high concentrations, often more than 10%, and always appears in the usual structural formula of the mineral.

The content is not however an exclusive criterion : certain elements present in lower contents are nevertheless considered as major elements because they play an essential role in the constitution of the mineral, such as chlorine in pyromorphite or iron in jamesonite for example.