As a FWIW, here's a photo of hemtite (iron oxide) in a rainbow of colors in quartzite as the host rock. This photo was taken by me inside a sheltered prehistoric native American excavation where they used these finely powdered leachings for making colors for pots and baskets - Salado Culture. This is a rare occurrance, given the volume of oxide and the breath of colors. Note sky blue if you pan to the right.

The location is along Coon Creek (off the Salt River) in the Sierra Ancha Mountains of central Arizona, NE of Globe. Coincidentally, these mountains also host small quantities of uranium and related prospector excavations, but nothing of commerical interest has ever been found here.