Answer: nielli

AnswerCrossword Clue
NIELLIDark, metallic alloys
niellito decorate by means of niello; treat with niello or by the niello process
niellipiece of metal or an object decorated with niello
nielliblack metallic substance, consisting of silver, copper, lead, and sulfur, with which an incised design or ground is filled to decorate metal
nielliany of several black enamel-like alloys usually of sulfur with silver, copper, and lead
nielliNIELLO, a black metallic substance
nielliornamental work so produced