Hardness 9 specific gravity 3.8-4.05
Refractive index 1.76-1.78 birefringence 0.008
Wear: excellent durability
Ruby refers to the ruby grade "corundum" which is red due to its "Cr, Cr" element. Its main component and sapphire are also "Al2O3". It has the hardness next to diamond and is one of the five most precious gemstones in the world. Ruby is the birthstone of July.
The English name "Ruby" of "Ruby" comes from Latin "Ruper", which means red.
History of rubies
Ruby is one of the most prominent colored stones in history. It has been mentioned four times in the Bible. In the ancient Sanskrit, ruby is called ratnaraj, which means king of precious stones.
In the first century A.D., Pliny the elder, a Roman scholar, described the hardness and density of rubies in his book natural history. The ancient Indians believed that those who offered rubies to Krishna would be reincarnated as emperors.
The color and characteristics of ruby
The element that makes Ruby appear red is chromium (CR). A ruby of good quality will be like burning blood in the sun. In fact, the chromium in Ruby makes it produce red fluorescence when it is exposed to visible light, which further improves the Ruby's red color.
Rubies formed in different parent rocks sometimes contain elements such as iron (FE) or titanium (TI). Iron will affect the fluorescence effect of ruby, so the ruby with high iron content will be darker; titanium will make Ruby produce blue or purple tone.
Origin of ruby
The most famous origin of "Ruby" is Mogok, Myanmar. The ruby here is produced from marble with less iron, bright color and strong fluorescence effect. It is the most valuable and rare origin.
At present, the most productive mining area of "Ruby" is Mozambique, Africa, where large reserves of ruby ore were found in 2009 and quickly became the world's main Ruby producing area. However, because of the high iron content, the ruby in Mozambique will be darker under the condition of high red saturation, and rarely have fluorescence effect.
In addition, Madagascar is also one of the producing areas of high-quality rubies. The rubies produced here will be slightly pink. The rubies produced in Thailand are from basalt with high iron content. Vietnam, Afghanistan, Tajikistan, India and Russia will also produce a certain amount of rubies.
It is worth noting that not all Rubies from Myanmar are of high value - mong Hsu, about 200 kilometers away from Mogu, also found a ruby mine in the 1990s. The ruby produced here is purple and dark, and the price is far lower than that of Mogu.
Quality classification of ruby
Color, weight, cutting and clarity are all important factors affecting Ruby value.
The most colorful ruby in Europe is called "pigeon blood", which originally refers to the ruby with strong fluorescent effect produced in Myanmar.
However, at present, some commercial appraisal organizations such as GRS will also call African ruby "pigeon blood red", which has no fluorescence reaction but has a certain red saturation.
Optimization of ruby
Due to the scarcity of rubies, the mining area will heat the ruby with dark color and purple blue color at high temperature of about 1000 degrees, and the heated Ruby will show more bright colors. Under the same quality, the carat price of heated ruby is only a quarter of that of untreated ruby.
Rubies often have cracks, and heated rubies are sometimes filled with lead glass to improve their clarity. The price of such rubies is only one tenth of that of untreated rubies.
Wearing and maintenance of "Ruby"
Ruby is a very durable gem with a Mohs hardness of up to 9. The unfilled Ruby can be cleaned by ultrasonic cleaner.