Semitransparent is optimal, objects should appear hazy through the stone.
Look for clear contrast between the stone and the star.
An ideal star consists of six, well defined rays.

Did you ever think you'd be telling your jeweler to show you the biggest, brightest flaw he's got? Well, if you're shopping for a star ruby, that's exactly what you're doing. That beautiful, perfect six rayed star is the same inclusion (silk) that you want to minimize in your faceted stone. So, here's the dirt on your favorite stars:

1. Six, well defined rays reaching across the entire face of the stone and easily seen under direct light.
2. The star is centered. (almost as likely in rubies as movies)
3. Clear contrast between star and surrounding stone.

Just like with the traffic signal red, this is simply the improbable ideal by which to judge reality's shortcomings. Look at it this way, just imagine the thrill of stumbling across a natural stone that comes close. The same color and clarity guidelines apply for star and faceted rubies, but for stars, there is a little more leniency. In addition, with stars you must consider transparency. From fully transparent to opaque, on this scale you are looking for a ruby that is semitransparent where objects will be hazy and a little blurry when seen through the stone.

Star ruby shopping checklist:

1. All the above elements for a quality star.
2. The less transparent the stone, the more important the cut. Opaque stones shouldn't have more than 1/4 total weight below the girdle. Semitransparent stones need more weight below the girdle to sharpen tone and make the star pop out. But, don't let cut kill what is otherwise a beautiful color and sharp star.
3. Watch for fakes. Is the star too clear? The bottom too flat? The red too vivid? The stone either too transparent or opaque? Some newer synthetics are better at hiding the truth, but after you see enough real ones, you'll be better able to pick out the wheat from the chaff.

Answer to quiz: a & b