Safely and quickly digging a tunnel under a building was the kind of project that would take a whole team of diggers… or a wizard. William had to admit that if he wanted his tunnel to last for a long time, he would need some engineers, or to spend more effort shoring it up himself… but it was sturdy enough. The building seemed to have a proper foundation, so the load was spread out across many places that the tunnel wasn’t, which helped a lot. Still, William made sure that the tunnel was firm-packed and steady. He didn’t want a building collapsing on him, nor could he afford it if it collapsed… not on him. Even though it was quick, it still took the entire day and Stefan’s assistance to create a tunnel a couple dozen feet long, and only a few feet wide. The tunnel currently ended under the middle of the building, at what was apparently causing the trouble.

“A rock.” Stefan looked at it, and William could see his eyes flick from the rock, up and down through the air. Of course, he wasn’t looking at nothing, but at the flow of mana. They were directly below the center of the formation, and the mana was flowing down through the floor toward the rock. The strange thing was, it wasn’t being absorbed by the rock, like would be expected of a mana attractive material. Merely, the flow of the formation was shifted from where it was supposed to be, and went down through the center… toward the rock… and then circled back up to the outer parts of the formation. Some of the mana flowed through the rock, but it didn’t seem to be absorbed at all, or at least not at any significant level.

William wondered how this rock could cause so much trouble. He couldn’t place its properties easily, because it looked just like a normal rock. Grey and black and all of that, not particularly smooth or rough. Maybe there was something inside of it, or below it still. “It sure looks like a rock. It’s late. We can deal with it tomorrow… and determine if it really is the cause.”

-----

In the morning, when William returned, he brought with him a special tool. Well, that was unfair to anything that was actually special, or a tool. Instead, he brought with him a small bar of metal. Nothing special about it, just plain iron. In terms of being magical… it had its place in some magical formations, but nothing too great. Still, this would help William verify his theory. He held the bit of iron out to the rock. *Clink*. “Yep, it’s magnetic.”

“What’s uh…” there wasn’t a word for magnetic in gevai, so William had just said it in English, “mag… net… ick?”

“Well, it’s this.” William shrugged. There hadn’t been any real reason to talk about magnets before, because they weren’t common. He’d seen some in his previous lives, and the ‘toy’ discs from Eclea had properties like magnets, but only in relation to each other. In a way, they were considered magic stones… and that wasn’t incorrect, but they weren’t seen as useful to magical formations. Mostly, they just messed them up… like this. William hadn’t really remembered that, because the probability of stumbling upon something significantly magnetic exactly where one was setting up a magical formation… it wasn’t high. William shook his head. “Anyway, magnetism makes certain kinds of metal stick together.”

“But it’s a rock.”

William raised an eyebrow, “And metal comes from?”

“... Rocks, mostly. But that one’s not particularly… metallic? So it’s mostly metal sticking to rock...”

“True… but,” William pulled out another tiny bar of iron, and stuck it onto the other one, “Magnetic things make other metals magnetic.” William shrugged, “That’s not exactly right, but you can see what you think.”

Stefan squeezed past William in the tunnel. He seemed surprised when he pulled on the bars and they resisted him… before coming free when he applied more force. He seemed even more surprised when they fell apart from each other. He put one back on the rock, then took the other about the width of the bar away from the rock, and sort of shook it around. Then he moved it over to the other bar, where it stuck. “Whoa, it really does stick. But it’s not really sticky.” He rubbed his hand over the bars and rock. “They’re still smooth, and there’s a pull when it gets close. But then, when there’s another one, that one also has the pull. It really does make it… magna tick.” Stefan played with the rock for a few minutes, then sighed. “I suppose we have to get this out of here.”

William nodded. “Yeah, it’s messing up the formation. It’s not that powerful, but the formation is pretty sensitive.” Many formations were, really. That was why you could only place so many defending a structure, or do so much to make an item magical… and there was also a limit to how much magical equipment one could have, though that was usually more limited by economics. Besides, weapons and armor had passive formations instead of active, so they barely interfered with each other. The only real problem came if you wanted to layer magic armor on top of other magic armor.

The rock was indeed larger than what they had revealed. While the top part was about the size of a large watermelon… or some of the similar melons they actually had here, as they dug down a bit more it became more like a small boulder. Unearthing it was quick, but removing it from the tunnel took most of the day. Part of that was because it was harder to use magic to help the process along, because it interfered with the magic… ever so slightly, but any interference was a pain. The biggest reason was that it was just a big heavy rock. They got the rock out, and determined that the formation was functioning normally. Now all they had to do was re-fill the tunnel, and their job would be done. William enjoyed playing in the dirt… but working in the dirt was just so tiring.