Why Are Colored Stones Precious?
Posted by Sarah on Jul 11, 2009
Although the terms precious gemstone and semi-precious gemstones are not used as much as they were in the past, ruby, sapphire and emerald are still the most popular gemstones available. Why are emerald, ruby, and sapphire the big three colored gemstones? One reason is hardness. Rubies and sapphires are both at 9 on the Mohs hardness scale while emerald comes in at 7.5. The chemical composition of ruby and sapphire is exactly the same called corundum and only if it is red do we call it ruby. All other colors of corundum are called sapphires but blue is the hue most people think of when they discuss sapphire. When a sapphire is not blue it is usually described with the dominant color such as pink sapphire. All three of these gems are rare in nature but so are many other gemstones. So why are these three more precious and generally more expensive than all the other gems? Each gemstone represents the purest examples of the primary colors red, blue, and green. Combine those primary colors with the exception hardness of each gem type and you can see why they have been so popular through the ages.
Since each of these gemstones are the best examples of primary colors in nature one should judge for color first. The best rubies are red not pinkish red or purplish red. Emeralds should have a highly saturated green hue rather than blue green, yellow green, or brownish green. Sapphires should be blue rather than purplish blue, greenish blue, or violet. Secondary hues in gemstones are almost always present and can be very beautiful but the highest percentage of primary hue should be the goal of a true gem collector. Clarity should be the second quality to judge in emeralds, rubies, and sapphires. Lastly, the quality of the cut should be your third quality to look at.