Here's another. I know the host rock was called something like ferricrete and it's from the volcanics. Just a guess. Any wye I was thinking it could be a type of garnet. Most the crystals are triangular in shape.
Been trying to track this one myself~ if your base material is ferrocrete its possible that the crystals are from a magnesium mineral. Interesting. If you can get a magnified view it may help. Triangular shaped crystal structure rules out garnets and tourmaline materials in my opinion
its also possible that it may be a zinc mineral like sphalerite.