I recently saw a large gold (plated) surface - larger than a hand. The effect the light played off of that metal was amazing, I've never seen the effect in small gold jewelry. Photographs and video just don't capture it. If Apple ever turns their attention to gold and manages to nail that effect, I would consider one of their devices just for that aspect.

Gold is really good at reflecting infrared which is why it was chosen as the coating for JWST's mirrors. I wonder if the colors just past visible on its way to IR would be just perceptible enough to give the look you are noticing???