'aragonite-rich' is a modern English compound formed from 'aragonite' + '-rich'. 'Aragonite' is named after Aragon (a region in Spain) and the mineral-name suffix '-ite'; '-rich' is an English adjective/suffix meaning 'having an abundance of'.

'Aragonite' entered mineralogical usage from the name of the Spanish region 'Aragón' (via Latinized/vernacular forms) and became established in English mineral names; the combining use of '-rich' in compounds (e.g., 'sugar-rich', 'iron-rich') developed in English to denote abundance, yielding compounds like 'aragonite-rich'.

Originally 'aragonite' referred specifically to the mineral named for Aragon; '-rich' historically meant 'powerful, wealthy' in Old English but later came to mean 'abundant in' when used in descriptive compounds. Together they now mean 'abundant in aragonite'.