As with faceted sapphires, blue star stones are most valuable.
Look for good contrast between the star and the stone.
Watch for rays that cover the face of the stone.
Make sure the star is as close to centered as possible.

Do you want to see a big, beautiful flaw? Find yourself a top quality star sapphire, and that’s what you’ll be looking at. The star is caused by the inclusion (internal flaw) called silk. The color determinants for star sapphires are the same as in faceted stones, but not quite as rigid because more emphasis must be placed on both the star itself and the stones overall transparency. With that in mind, here’s the main things to look for in star sapphires.

1. Blue is the most valuable, black with a white star is least expensive.
2. An ideal star is 6 rayed, centered, in good contrast with stones background, with the rays reaching across the face of the stone.
3. You’ll never find a stone with all the elements in #2.
4. Think in terms of degrees to which each stone meets those criteria.
5. You are looking for a stone not too transparent, not too opaque. You should be able to see newsprint through the stone, but the type should be blurry. This is called "semitransparent."
6. Look out for an overabundance of surface cracks. These flaws are common in star sapphires, but too many could weaken the stone, and it could also mean the stone has been dyed for color enhancement.
7. The less transparent the stone, the more important the cut. More opaque stones should have as little weight as possible below the girdle (edge cut).
8. Look for high domes and rounded bottoms. Except on black star sapphires which are cut more shallowly to enhance the star effect.
9. Watch for fakes. Is the star too clear? too perfect? Is the bottom too flat? The color too vivid? The stone either too transparent or too opaque?

Some of the newer synthetics are better at disguising themselves, but the above indicators are still good warning signs that you could be looking at a star-wanna-be and not the real thing.

There you have it. Now you can go on your own star search and come home a winner.

Answer to quiz: c