The stone at Torin Quarry

I'm currently doing the quest for the Halcyon Order that involves bringing them the big stone from Torin Quarry. The problem is... it's not there. I fear this is because I explored the quarry before I even went to Vooriden, and Virgil, for some inane reason, decided to pick the stone up, so I took it out of his inventory and put it back. I'm afraid it disappeared because the game thought I was throwing it away. Is there any way to get it back?

Also, I know there are a few similar stones in Ashbury. As far as I remember they were the same thing, labelled the same and all, so I'm hoping it's the same item in the game's database. Sounds like it's worth a try. I really don't like the idea of not ever being able to finish this quest, guess I'll just have to be more careful next time.