How Can You Tell The Quality Of A Ruby?

As one of the world’s most popular gems, many ask what makes a ruby so beautiful and how does one tell if the ruby they are looking at is of high quality? This is a great question! You don’t need to be a gemologist to understand the quality and value of a ruby, but we all might benefit from more education shopping for rubies. In this article we will tell you all you need to know about rubies and answer the common question “How Can You Tell The Quality Of A Ruby”.

The History Of Rubies

Many cultures have considered rubies the gemstone of kings. Historically, the stone was worn in many battles as it was thought to be a stone of protection.  Some cultures even went as far as inserting the stone into the skin as they believed this would protect them. Ruby goes back as far as the Bible and is still ever so popular. With its intense red color it only makes sense that it also symbolizes wealth and passion. It is the birthstone of July and Cancer and both the 15th and 40th anniversary stone.

Historically, all red stones were called rubies from the Latin word, ruber or “red”. It wasn’t until ruby was identified as corundum did it separate them from other luscious red stones. You may have heard of the the famous 14th century Black Prince’s Ruby in the British Imperial Crown. Well, this “ruby” is actually a red spinel and was thought to be a ruby until the 1940’s.

What is a Ruby?

Ruby is a variety of the mineral corundum that contains chromium, a rare element that imparts the red color and fluorescence. Both ruby and sapphire are corundum, just with different colors. Gem-quality red corundum is considered ruby, while all other colors of gem-quality corundum, including colorless, are sapphire. Since sapphire can also be found in the “ruby” color, there can be a very fine and subjective line between pink sapphires and red rubies.  In a fascinating article, Richard Hughes observes that before the 20^th century, pink was considered a “light red” and some rubies were indeed described as “pink rubies.” Over the course of the 20^th century, “someone decided that pink was not red,” and the first references to pink sapphires appeared. The mineral corundum forms in metamorphosed crystalline limestones and dolomites, as well as other metamorphic rock types such as gneiss and schist. It also occurs in igneous rocks, such as granite and nepheline syenite.

Ruby from the island now known as Sri Lanka has been mined since 543 BC & ever since. It may be the  first ruby to appear in Europe in Etruscan jewelry. What is now known as Myanmar (until recently, Burma) has been a primary source of fine ruby for somewhat longer, since 600 BC. Recent political turmoil has severely limited availability from this historic source.  As an oxide of aluminum & often a byproduct of aluminum mining, ruby is found through Asia. Recent discoveries in Mozambique & Madagascar have become principal sites for exceptional ruby but reserves are likely to be limited. 

Many are familiar with the 4 c’s of grading diamonds, and they want to know if rubies are graded similarly. Most rubies do not come with a grading report; however, like a diamond, color, clarity and size are significant in pricing. The most important of these factors is vividness of color. The finest ruby has a pure, vibrant red. Gemologists assess color by considering hue, tone, and saturation. Gemstones often have a secondary hue in addition to a primary hue. In red gemstones, the most common secondary hues are purple and orange. Connoisseurs consider a pure red or red with just a hint of purple to be the top quality in red gems. As the hue moves further from this ideal, value drops. That doesn’t mean that purple reds and orange reds aren’t beautiful in their own right. In fact, few gems approach the ideal red. Clarity grades are less important in red gemstones than in colorless gems such as a diamond. That’s because the darker color helps to hide imperfections in the stone. In addition, eye-visible inclusions near the center of the gem will be more noticeable than those toward the sides. Among the rarest gems in the world, most rubies undergo heat treatment to improve their color — and increase their value.