User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-5043481-20130202132942/@comment-5043481-20130203160839

None of these explanations are very good... If you split a rock in two, sure, you have two rocks, but you have the same amount of rock. You can't trick the crafter that easily.

And for those of you who don't know what they do. What they do is take one ore/bug and when combined with it make another one. So you start off with one union ore, and end up with two. Great for getting rare bugs/ores.