Rubies and sapphires are both precious gemstones but many may not realize they are actually the same mineral, which is corundum. Corundum comes in many colors. Every single color of the mineral corundum except for red are known as sapphires.
Red corundum is known as ruby and there is a reason that red corundum is the only colored variety of this mineral with a different name. Both gems have the same chemical composition and the same mineral structure.
The gems get their colors from trace amounts of impurities that can produce red, yellow, green, orange, blue and purple gems. Every other color of sapphire except for blue (and obviously red) are known as fancy sapphires.
What Makes A Ruby Different.
Ruby gets its red coloring from chromium in the gem. Although chromium can produce a light pink color, there has to be a certain amount to give it that distinct red color for it to be considered a ruby instead of a pink or orange sapphire. For the gem to be attractive, it needs to also have clarity.
There is such a thing as red sapphire, but it does not occur naturally. This gem only occurs when a piece of corundum is infused with beryllium and treated with intense heat and pressure. So when you see "red sapphire," know that this is not a ruby. It's the same mineral as ruby but it doesn't have chromium, or if it does, it doesn't have enough chromium to be a classified as a ruby.
Rubies are known as a stone of kings and are symbolic of power, wealth, and protection. In Hindu lore, rubies are known as the kind of precious stones and are deemed more valuable than any other gemstone. The Mani Mala speaks of the Kalpa Tree which is a symbolic offering to the Hindu gods. This tree is entirely made with precious stones--sapphires, diamonds, and other gems with rubies as the fruit the tree bears.
The Harita Smriti even speaks of rubies as a form of worship.
“He who worships Krishna with rubies will be reborn as a powerful emperor. If with a small ruby, he will be born a king.”
Legends have it that possessing a ruby benefits and protects its owners' estates and helps them to grow their wealth--and acquire more gems. For protection, many would wear the ruby as a talisman (think jewelry) and this includes personal protection. Some believe that wearing a ruby as a ring or bracelet on the left arm would allow the wearer to live peacefully.
The color of a ruby is also linked with blood. People who risked their lives were often believed to have a special connection with the gem. The ancient Burmese believed that rubies were the stone of soldiers and only those who had the gemstone physically inserted into their flesh would gain its benefits--including safety from wounds caused by spears, knives, swords or even guns. That may seem a bit gross, but even today we wear piercings and even ear gauges.
Rubies often have an inner light that seems to glow (so do garnets) and many often attribute this to an inner fire. Some believe that a ruby placed in water could bring the water to a boil. Hiding it in a wrapping, the gem could reveal itself by shining brightly.
"The beautiful and terrible figure of a dragon. If this is found on a ruby or any other stone of similar nature and virtue, it has the power to augment the goods of this world and makes the wearer joyous and healthy."
--Ragiel, The Book Of Wings.
In ancient times, many believed that rubies inhabed spirits--especially if the gems were uniquely rare or beautiful. The idea the gems are sentient beings has been around for a while and even today, I feel that crystals are living beings. After all, they are made up of energy as with all matter.