Central Diamond Center is a full service jewelry store, offering custom designed jewelry, jewelry repair, appraisals, and gold buying. EL-EM TRADING Co. Inc was founded in 1989, and has been doing business as Central Diamond Center. The name EL-EM Trading stands for the initials of all five of our family members.Central Diamond Center stores are located in Richardson, Texas and in one other location in the Dallas metropolis to better serve you.