Sterling Jewelers recently sent JCPenney a pair of letters asking the retailer to stop selling items it claims are similar to Sterling’s Jane Seymour collection. “JCPenney Corporation Inc. is copying, reproducing, and/or distributing jewelry that is substantially similar to the Jane Seymour Designs,” said a Nov. 16 letter signed by attorney John J. Cunniff. The letters were made public in a lawsuit against Sterling filed by L.A. Gem & Jewelry Design, the ­disputed jewelry’s manufacturer, in U.S. District Court, Central District of California, on Dec. 15. In its suit, L.A. Gem & Jewelry Design says its designs do not infringe on the Seymour line and charges Sterling’s letters caused it to “suffer substantial injury and damage.”