'gem-decorated' originates from Modern English, a compound of 'gem' and 'decorated', where 'gem' ultimately comes from Old French 'gemme' (from Latin 'gemma') meaning 'bud, jewel', and 'decorated' derives from Latin 'decoratus' (from 'decorare') meaning 'to ornament'.

'gem' entered English via Old French 'gemme' (from Latin 'gemma'), and 'decorate' came from Latin 'decorare' through Old French 'decorer' and Middle English forms; the compound 'gem-decorated' is a modern English formation combining these elements.

Initially the elements meant 'jewel' and 'to ornament', and over time the compound has kept the meaning 'adorned with jewels' in contemporary usage.