Rego purification

This came up specifically from thinking about a glass-maker Verditius, but it could cover a lot of things. Suppose you have a big pile of an impure substance. Creo would let you change it into a big pile of pure substance, or make the pure stuff from scratch, but could you use Rego to separate out the impurities?

Let's start with something fairly simple, Sift the Fallen Wheat. ReHe(Te) 5 Touch, Moment, Circle. Given a pile of grain inside the ring, this spell will separate the wheat kernels from any chaff, small stones, etc. You're left with one pile of good grain and one pile of trash.

Now for glass, the quality of the potash and sand has a big effect on the glass. You want to make Venetian-quality glass without paying to import materials from Venice. Re(In)Te 4 Touch, Moment, Circle to take a large quantity of average material and separate it into a small pile of high-quality sand, and a big pile you throw away. The Intellego req is to figure out which bits of sand would be best for glassmaking, like the example in covenants of InHe to pick good wood for carpentry. Would that work?

I can't see why it wouldn't work. I would think that for a Magus to invent such a spell he would need to have a good understanding of the mundane process, either through a Craft skill or through spending a certain amount of time studying a master craftsman at work.

I also don't see a problem here. Rego is very often a cheap alternative to creo and mor durable than muto. But don't forgett that you might need a finess role to do it properly ...