Last I heard, Burr, Patterson & Auld is Delta Zeta's official jeweler. The jewelry they have designed for DZ is available for order from the deltazeta.org web-site, with the exceptions of badges, which can only be ordered through National Headquarters. I can only speculate that this is done to keep non-members from purchasing them....
You can see basic designs of all NPC group badges on
http://www.npcwomen.org/about/badgeposter.pdf
The Delta Zeta badge is a golden lamp, with a diamond in the flame, & four seed pearls at the base of the lamp. Delta Zeta does not vary the design of the badge--well--there is one slight variation, you can have the diamond set in one of two ways (one is Tiffany, I can't remember the other).