This is an interesting specimen in that it was identified as both columbite (Fe2+Nb2O6) and samarskite (YFe3+Nb2O8), the only difference being the presence of Y.? Here is a comparison of 2 different sides, one with a columbite crystal and the other a more shiny fracture.? The latter shows the Y, conspicuously missing from the columbite side.
