Which Gemstones are Precious?
by diywealth on Jul.29, 2009, under diy
The most admired gemstones emerald, ruby, and sapphire were in the past often called precious gemstones while all other colored gemstones were referred to as non-precious or semi-precious. Why are emerald, ruby, and sapphire the big three in colored stones? One explanation is because of their unique hardness. Rubies and sapphires are both at 9 on the Mohs hardness scale while emerald comes in at 7.5. Rubies and sapphires are both chemically the same material called corundum (Al2O3) but if it is red we call it ruby. All other colors of corundum are called sapphires but blue is the color most people think of when they are talking about sapphire. Other colors of sapphire are usually qualified with the color name such as pink sapphire. All three of these gemstones are rarely found in nature but so are many other gems. So why are these three more precious and generally more expensive than all the other gems? Each gemstone exhibits the finest examples of the primary hues 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 thoughout history.
Always remember when evaluating these three gemstones that color is paramount. The best rubies are red not pinkish red or purplish red. Emeralds should be green rather than blue green, yellow green, or brownish green. Sapphires should be blue rather than purplish blue, greenish blue, or violet. Secondary colors in gemstones are almost always present and can be desirable but the highest percentage of primary hue should be the goal of a true gem collector. Once you have judged the color you can move on to judging the clarity next. Finally, the quality of the cut should be your third quality to look at.
