Geppi's publishing ventures in the comics field saw him create Gemstone Publishing Inc., which was formed in large part from other purchases. In 1992, Diamond bought Ernst Gerber Publishing (publisher-author of the "Photo-Journal Guide to Comics"). E. Gerber Products, LLC is a Diamond-affiliated company started by Gerber in 1977 which sells Mylar bags as well as "acid-free boxes and acid-free backing boards" for comics collectors to store their collection in. In 1993, Geppi bought Russ Cochran Publishing. Long-term EC Comics fan Cochran auctioned Bill Gaines' personal file copies of EC publications, as well as most pages of original EC artwork (which, almost uniquely, Gaines had maintained ownership and possession of), before being granted the reprint rights to the EC back catalog itself. Geppi included Cochran's publications — and Cochran himself — under his new imprint, Gemstone Publishing.