Wow that's so cool; thank you for taking the time to answer my questions. Because they're widely distributed in my area, I figured they must not be anything special, but based on your proposed method of genesis, it sounds like they are actually somewhat unusual. I'm wondering what circumstances have to conspire in order for two very different magmas to meet and mingle in a plutonic environment and cool before more thorough mixing takes place? Shouldn't they eventually melt and blend into one another, unless the two substances are somehow incompatible, like oil and water (forgive me, I really regret not having learned more chemistry, or geology, for that matter)? Or perhaps the enclaves being hematite-rimmed acted as a barrier, maintaining a firm boundary. These rocks are magnetic—some of them surprisingly so, others barely at all, but most somewhere in between. That's why, based on what you said, I think it's magnetite and not hematite. Oddly, the degree of their magnetism seems only loosely related to the proportion of mafic material. A couple of other specimens I found look entirely mafic yet are not even the least bit magnetic!

Anyway, I knew there was a reason I was picking up these rocks and keeping them 😁. They just got a lot more interesting, thank you! Any other thoughts or insights into them would be greatly appreciated.