Labradorite
Labradorite looks like unremarkable grey stone until it catches the light at the right angle and flashes blue, gold, or green. The effect, labradorescence, comes from light interfering within microscopic layers inside the crystal rather than from any pigment.
It was described from the coast of Labrador in the 1770s, though Inuit tradition on that coast long predates the naming and holds that the lights within the stone are the aurora caught in rock.
Because the flash only appears from certain directions, no photograph of labradorite is entirely honest about it.