This boulder is a glacial erratic in New Jersey. Can anyone tell if it's granite or gneiss? When you look at from the side, there appears to be foliation... but when you look at from the top or other angle, you don't see layers and it looks like granite. We're preparing signs for a nature trail and any help would be appreciated! Thanks so much
I would call it gneiss because of the foliation. When you look from other directions, you don't see it because you are looking down, more or less, on one layer. You should be able to see some foliation if you look at a cross-section of the layers from another side, but sometimes you get more of a lineation where the crystals align in one direction only.