Ceradyne, Inc. has joined the Russell 3000(R) Index, a leading broad-market equity index published by Frank Russell Co., effective July 1, 2003. The final membership list published on July 9, 2003, also included Ceradyne in the Russell 2000(R) Index. The Russell 3000 Index is composed of common shares of the 3000 largest U.S. companies ranked by stock market capitalization. According to Frank Russell, this index accounts for approximately 98% of the investable U.S. equity market. From this broad-based index, the 1000 largest are included in the large-cap Russell 1000(R) Index, with the remaining 2000 included in the small-cap Russell 2000 Index. Russell U.S. stock indexes are reconstituted annually and are widely used by managers for index funds and as benchmarks for both passive and active investment strategies.

For additional information, call (714) 549-0421, ext. 261, e-mail jmoskowitz@ceradyne.com or visit http://www.ceradyne.com .