I think the correct term is impure (imperfect) Grossular Garnet which is a Calcium-Aluminum mineral species of Garnet but in this case, where the Cacium was partialy replaced by Ferrous Iron and the Aluminum partially replaced by Ferric Iron. Yeah, I had to look some of the information up! However, I have dug many specimens of Grossular Garnet over the years, mainly outside of Burnsville, North Carolina but also in some other areas of North Carolina and a few in Tennessee. I still have some that I have dug and one is a perfect Dodecahedron crystal about the size of a Golf ball but it is butt ugly due to the Iron composition it is partialy made up of.
Wow, that bad boy looks like red andradite garnet crystals and calcite crystals on matrix, interesting, this is a nice matrix, I'm dead sure those are red andradite garnet crystals, this should kill the mystery.