A "diamond merchant" is a person who buys and sells diamonds for a living. They are involved in the business of trading diamonds, either directly to customers or wholesalers. Full definition
Sharpton came to euologize the kid that had been accidentally hit with a car, and made a comment about «diamond merchants in the neighborhood.» (religion.blogs.cnn.com)
«It's so convenient to Harry Winston (a local diamond merchant) and Hamburg Heaven.»» (si.com)
The owners included Prince Ivan Kanitovski, who was killed by Russian revolutionaries; Simon Mencharides, who died with his wife and child in a car accident; and French diamond merchant Jean Baptiste Tavernier, who was «torn to pieces by wild dogs in Constantinople,» the Times said. (cnbc.com)