Its all in the sapphire shades
Look out for shades of gray and black in blue sapphires, lowers v, making these stones not desirable for resale. But, if the stone is just for you and you like that hue, go for it.
Sapphires of any other color are called fancy sapphires, and in order of value they are:
Padparadscha: Is a beautiful pinkish-orange. These stones are extremely rare and very expensive. Make sure both the pink and orange can be seen simultaneously as some jewelers may insist that an orange sapphire is Padparasdscha. Watch for "brownout," you are looking for a light to medium, vivid pinkish-orange.
Pink: These gorgeous stones can get a little tricky. Since pink is basically light red, some may be sold as rubies. But true pink sapphires will have a purplish hue which make them easy to differentiate from their red cousins. Again, look for light to medium tone and watch out for brown or too much purple.
Orange: Think medium-dark red-orange to avoid confusion with the light pink-orange of the Padparadscha, which can carry twice the price. Don’t be surprised to see some orange sapphires with yellowish tint as well, but the darker reddish stones are the most valuable in this category.
Purple: Medium-dark reddish tones give these stones a plum color in their most desirable state. Make sure you don’t see too much gray or brown. Purple sapphires can also fall into the Color-change category, as they may appear violet indoors and blue when you go outside. This is okay, even valuable, just so long as the color change is pure and strong.
Yellow: Since you are ideally looking for a vivid, light-yellow with high transparency and, perhaps, some hints of orange, clarity becomes more an issue with these stones; as flaws will be much more visible.
Green: The least expensive of all the sapphires, these black sheep range from yellow to blue-green and preferably will have medium to dark tones. If you are looking for a vivid green gemstone, try emeralds or garnet.
Whichever color you choose, always apply the consistency of color tests which were listed at the beginning of this section. As you are inspecting the color, the issue of clarity will make itself clear. And remember, unless you are a collector, pick any color you like. They all are beautiful. So if green happens to be your favorite color, don’t let the fact that it is the least valuable sapphire stop you from buying one. The possibilities are endless, enjoy the diversity.