It Has a Unique Color

  Yellow sapphires come in tones from fancy light to vivid yellow. "Fancy" refers to a stone's color depth; typically, smaller stones are lighter in weight than larger stones. Some pale stones have an almost greenish tint to them and are considered "fancy light" yellow or "fancy" greenish-yellow by the Gemological Institute of America (GIA), the world's foremost authority on gemstones.   Vivid yellow sapphires are often more expensive but can be found at a lower cost if you look for stones that aren't as saturated with color — like gems with more golden or honey tones.