You’d be hard pressed to find someone who doesn’t love rubies, with their beauty and incredible color. Their durability and value is legendary. (Use them for shoes, however, and they can get a house dropped on you.) For those born in July, rubies are a special birthday gift they didn’t even have to ask for.
In their finest quality, rubies are a brilliant red almost unmatched by any other gemstone. (The Black Prince’s Ruby, found in the British Imperial State Crown, is really a huge red spinel. Had everyone fooled for a long time.) Yet there are lots of rubies that are not the finest quality. What makes a good ruby?
First, that brilliant red color. Rubies are red. A “light” ruby—meaning leaning toward pink or purple rather than red—may be called a ruby, but it’s considered in gemological circles to be more accurately described as a pink or purple sapphire.
That’s right. Rubies and sapphires are the same type of gemstone (corundum) separated only by their color. We call blood-red corundum “ruby,” but all other corundums are called sapphires and described by their color (blue sapphire, yellow sapphire, etc.)
Second, rubies should be transparent,and free from internal inclusions, the “stuff” you see in all but the very finest rubies—fractures, crystals, needles, and zones of color. The exception is when there are needles (long thin crystals) at 60 degrees to each other that have grown inside the stone. When light reflects from these inclusions, you see a six-legged star that appears to float just under the surface. Too often, star rubies are purplish and not as transparent as they should be, but they are still treasured because of the star phenomena. But when the needles are so fine as to be virtually invisible, and the stone appears to be transparent, well. Then you really have something that is almost magic.
With their deep red color, rubies are a stone of passion. In addition, they are incredibly hard and durable, and will last a lifetime. That makes ruby an excellent stone for an engagement ring if you want to have something different from a diamond. Even better if it’s your birthstone.