Both metallic iron and magnetite, $\ce{Fe3O4}$, are magnetic. Now, iron is grey in color, whereas hematite is black, so that they can be distinguished visually. Now, I have a powdery mixture of iron/magnetite and lighter grains so that the mixture appears grey, making visual differentiating a bit tricky. I assumed it was iron, but someone else claimed it could also be magnetite, and now I'm not sure.
Is there a really easy way to be sure what I am dealing with? I don't want to do an XRD just for this.