The Sigil Stones are also capable of being duplicated.

Th duplicate, equip your arrows (in multiple of ten, no more than fifty or the game freezes) with no weapon equipped, Look at ground and attempt to punch it, before the punch is completed go into your menu, try to unequip your arrows (you will get a message saying that you can not do that), then drop whatever item you want duplicated.

Now, once you dupe the Sigil Stones you can set one aside and use the others to enchant your armor and weapons. I recommend that you dupe the Sigil Stone with the Chameleon attribute. You need enough stones to enchant an amulet, two rings, a pair of boots, a set of greaves, a set of guantlets, a cuirass, a shield, and a helmet -- This gives you 90% chameleon and no one can see you when you are in sneak mode, not even in daylight two feet away. If you are not in sneak mode then enemies can hear you and will attack. This come in handy with Oblivion gates, you can go through the entire thing undetected, the same with quests.

You can do this with any Sigil Stone and get 90% of of whatever the attribute is.