'agate-studded' originates from English, specifically the compound of 'agate' and the past-participle 'studded', where 'agate' meant 'agate (the stone)' and 'studded' comes from the verb 'stud' meaning 'to set with studs or to ornament'.

'agate' came into English via Latin 'achates' from Greek 'ἄχάτης' ('achates'), while 'stud' (noun/verb) traces to Old English roots (e.g. 'studu'/'stōd') meaning a support or ornament; the past participle 'studded' was used to describe something set with small ornaments, forming the compound 'agate-studded' in modern English.

Initially it meant 'set or decorated with agates,' and over time this literal meaning has remained essentially unchanged in modern usage.