what is the niello technique?

what is the niello technique?
Answer
Brief Explanations:
Niello is an ancient technique. It involves a black - colored alloy made of sulfur, silver, copper, and lead. This alloy is melted and inlaid into engraved metal surfaces, usually silver, to create decorative patterns.
Answer:
Niello is a technique where a black alloy of sulfur, silver, copper, and lead is melted and inlaid into engraved metal (often silver) surfaces for decoration.