The most important of the gem families, corundum provides us with two of the best-known stones: ruby and sapphire. The popularity and price of these gemstones remain strong due to the beauty, durability and versatility of the material. Ruby & Sapphire all fall under the corundum family. Ruby is corundum that has a purplish bluish-red to yellow-red color. The finest color is pure red with a hint of blue, as seen in glowing coal or red of a traffic light. Sapphire is more abundant than ruby because its coloring agents(impurities) are more common than those of ruby. The most valuable color is blue.