Ruby, the birthstone for July, is a variety of the mineral corundum and is considered one of the four 'precious' gemstones, along with sapphire, emerald and diamond.
It is the most famed and fabled red gemstone, and one of the most popular choices for all kinds of jewelry.
Description of ruby
Ruby's color is seen to be its greatest asset. Traditionally, it can range from near colorless to a vivid, deep crimson color, as long as the primary hue is red – but in the United States, a minimum color saturation must be met or else the stone is called a pink sapphire. The most preferred color is a deep blood red with a slightly bluish hue.
Ruby is famous for its special luster, caused by minute inclusions which cause it to be fluorescent. The stone is also pleochroic, and will sometimes display a lighter and more intense color when viewed from different angles.
It's also one of the hardest natural gemstones in the world, measuring at 9.0 on the Moh's scale and falling below only diamond and moissanite. However, it's still vulnerable to chipping.
Burma was, for centuries, the world's greatest source of ruby, but Burmese ruby rarely exceeds several carats and large, flawless stones can be worth millions of dollars. Rubies have been mined across the world, from India to Colombia, and from Japan to Scotland.
History of ruby
Ruby is mentioned four times in the Bible, linked with beauty and wisdom. In the ancient language of Sanskrit, it's called ratnaraj, or “king of precious stones”.
The gem has been at the heart of various legends over a timespan of centuries. Ancient Indians believed rubies enabled their owners to live in peace with their enemies, and in Burma warriors would insert them into armour and even their own flesh, believing that it would make them invincible in battle.
During the development of the western world, ruby became one of the most sought-after gems of European royalty and the upper classes. Many in the medieval era wore rubies to guarantee health, wealth, wisdom, and romantic success.
The first synthetic ruby was produced in 1837, but it was not until 1903 that laboratories were producing it on a large scale.
Value of ruby
Like with diamond, the value of ruby is based on color, clarity, cut and carat – but the most important attribute by far is a ruby's color. The brightest and most valuable "red", sometimes called "pigeon blood", commands a large premium over other rubies that are otherwise comparable.
Clearer stones also command a premium, but a ruby without any needle-like inclusions may indicate that the stone has been treated and can reduce its value.
A fine ruby is more valuable than a diamond of corresponding size and quality.
Treatment of ruby
Ruby treatment includes color alteration, improving transparency by removing inclusions, and the healing or complete filling of cracks.
The most common treatment is heat application to improve color and remove purple tinges and blue patches. Most, if not all, rubies at the lower end of the market are heat treated, which has led to the process being considered very acceptable.
In recent years, rubies have been treated by lead glass filling which dramatically improves the transparency of the stone, making it more suitable for use in jewelry.
Ruby's popularity in fine jewelry is down to its bright red color. The stone is seen as an ideal romantic gift because it represents our most intense emotions – love, passion and fury.
People are naturally drawn to its lush color as a symbol of wealth and success, and coupled with a tough exterior it's easy to see why ruby is so sought-after.