I tried using a workbench, but it did not show up in the options. I was wondering if there was some other arcane method of improving it, like tossing it in the Atronach Forge, etc.?
Jewelry can not be improved as the only stats they have are from enchanting. Also, once an item has been enchanted it also can not be altered, this includes quest given items. However, the stats can vary on some quest rewards, often depending on the players level.