First of all, Alessandra Torrresani will be among the guest stars in Warehouse 13‘s third season (which will premiere 11 July). But beyond that episode, I need some sort of explanation of the premise of the show which will justify my continued viewing.
I have settled upon this quasi-explanation:
The power with which the artifacts are infused is (sometimes) imagination. An artifact (anything changed in form by a sentient being for a purpose) is initially made with creative energy (imagination). Therefore, these powerful prototypical artifacts canot, by definition, be duplicated. How Lizzie Borden’s mirror fits into this is unclear, since mirrors have been around for quite a while, but let’s presume a second mechanism for adding power to an artifact. That would be the attachment of emotional significance to an item (such as a compact mirror) and would be an elaboration on the concept of sympathetic magic. Again, the object cannot be duplicated, as a copy would not retain the emotional significance.
The next problem would be from whence the power comes. We know the artifacts are affected by electricity. We also know that some chemical mixture (purple goo) renders them inert, and they can be contained in a special sort of bag safely. All this points to magnetism being behind the artifact’s power. The magnetic force probably is not what powers the object, but it is used to channel and focus another, naturally abundant force such as gravity. The test for this theory would be how artifacts work in deep space, far away from a gravity well.