I always played where if a character had the amulet they would not be affected by spells and neither would any of their objects or followers. But in my last game a player brought up the argument that it would only stop spells from affecting the character and not his objects so he should be able to shatter my Amulet. What is the official ruling on this?

The Amulet cannot be shattered at all. The Amulet prevents all Spells from affecting that character including all his Objects & Followers...

I would like to raise a discussion here. This is how we have interpreted spell targeting:

A spell that targets an opponent's object, follower, gold, spell, or other possession is considered to be targeting both the character and the possession. However, a spell that targets your own possession is only considered to target the possession, not your own character.

So for example, consider the Hydra Spell. The Hydra Spell works only on Spells that target characters. I believe it is universally accepted that I may cast Acquisition on your object, then cast Hydra in response to cast Acquisition on more characters. But, I can't cast Alchemy on my object and then respond with Hydra to multiply the Alchemy spell (as Alchemy doesn't target a character - it targets only my object).

Extending this, if you cast Shatter on an opponent's object, then it targets both the character and object. But if you cast Shatter on your own object, it only targets the object and not you.

Would you say, then, that you could Shatter your own Amulet?

EDIT: No, of course not.....you can't cast spells. Sigh, too much to remember...

Hopefully the above general points were useful though...

No you cannot cast Spells when you have the Amulet!

Haha, darn. You're right. All of that analysis and I forgot the most important thing.

Well hopefully at least I raised some points about spell targeting.

All hail the invincible Amulet!

The Hydra Spell gives rise to a hole spectra of weird combinations and questions. I'd say/guess it would take too much time for ffg to address them all in rules, on cards or even in a future (mythical) faq.

So.. where does that leave us?
Well, in this case I'd say it's easy. Even though the wordings does opens for the loophole Artaterxes found and described I'd still say no. The Amulet cannot be shattered using spells.

Ha! Good point, I didn't think of that either

Wait for someone to drop it (or take it from them and drop it) and then cast Destruction on it.

Pretty much the only way.