Artist John Avon has illustrated 169 Magic cards. And while his lands are consistently very popular, he's done more non-land cards than most artists have done cards at all.
The first step of the creation of a card's art is its art description. The art description tells the artist what the card will do, what its flavor is, and what the mood of the illustration should be. Here were the instructions John was given for this artifact:
Action: this is a small, beautiful, obviously delicate faceted crystal container for a soul. It is vaguely humanoid, and set into a base of gold and silver. a fine golden chain runs from the base to a small pointed hammer that is etches with runes. this is an item of beauty meant to be used. once.
Mood: You get one use -- and that's all you need.
With that art description to work with, John submitted a sketch to Magic's creative team with a few notes:
With an artist like John Avon, the creative team is happy to accept a note like "Swirls of Magic" in the sketch phase. Their only request was to make sure that the little hammer was emphasized in the final version.
And here's what the effigy in question looks like in Magic 2011 packs: