Kings in the Gupta empire owned huge copper, gold, and iron mines. With the gold and copper metalworkers made coins. The coins were engraved with Gupta rulers. The pictures on the coins represented famous things that ruler did. They used the iron to build great things like an iron pillar called Meharauli. Meharauli is a pillar made of solid iron and stands 25 feet tall, and weighs about 13,000 pounds. It is engraved with a story about the accomplishments of a Gupta emperor. The pillar is almost rust free after 1,600 years.