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v. Simple past tense and past participle of hallmark.

adj. Stamped with a hallmark

"(02 June 2006) - New from London-based design group oki-ni and world-famous Japanese graffiti artist Daisuke Sakaguchi, these street-lux mobile phone accessories are made from "hallmarked" sterling silver and attach with a plastic-coated stainless steel wire loop."

hallmarked    hallmarking    hallmarks