Help me decide what this artifact does, please!

[Jeremy Ackerman-Yost]

...
b) It's not an artifact. It's is someone's soul...

c) It's not an artifact, it is prison of a fallen angel.

I like these two combined with some of the earlier ideas for flavor (notably my tear idea and the heirloom bit) because they will allow you to have a great deal of control over what powers you let the thing manifest. If the PCs have to "attune" themselves to the spirit/soul/ghost/purpose of the thing, you can let them have it at first level, and just slowly allow it to manifest more and more powers. Or you can even have them learn to communicate with it to access those powers.

Personally, I still like it being a soul, or the remnant of a soul from a very powerful being. But the prison motif has some promise as well (think the Troll gods trapped inside Bhelliom in the Elenium). The PC would have to learn to impose his will on the inhabitants, or else cut a deal with them, to use their powers. The PCs could be given a bargaining chip in that the prisoners of the gem can't act upon the world alone, and need the PCs to channel their power. Reasonable grounds for a partnership, that.

 

[Fade]

2 - It is the headstone of a powerful scepter long thought to be lost. What scepter? Err... the Imperial scpeter. Yep. He who wields the Imperial scepter has a legitimate claim to the vacant imperial throne. Of course, first you need to find the rest of the scepter. 'Cause atthe moment all you have is a pretty gem that makes you a tempting target.

Then you need to find the imperial throne. Then the empire. Then some subjects....

 

[Mal Malenkirk]

Then you need to find the imperial throne. Then the empire. Then some subjects....

Nay. The special power of the Scepter is that all you have to do is take a huge cauldron, fill it with gold, stir it with the scepter then put it into the oven at 1200 degree farhenheit for about 3 hour.

Tadaa! Here's you Shake'n'bake empire.

 

[Aeolius]

“Bake the hall in the candle of her brain!” (obscure reference, I know, but somebody had to!)

Perhaps the orb holds the combined wisdom of a thousand sages (each “sparkle” being the soul of an ancient scholar).

Perhaps the orb is a “cursed” crystal ball of hypnosis. The item could also be intelligent and hold mysterious powers.

The orb is a crystal repository for life-energy. It slowly transforms its owner into a vampire.

Though the most likely solution would be... Gristle the garden gnome’s lost lucky bowling ball.