The Neodymium Daylight Spot Bulbs are produced using glass that has been impregnated with a type of 'rare earth' known as neodymium, which gives a blue hue. When neodymium is present in the glass of a spot bulb it filters out yellow light produced by normal spot bulbs, this then creates a whiter light that is more natural in appearance. Neodymium filtered light can also enhance the appearance of greens and reds within an enclosure.