The name ‘Ruby’ comes from the Latin word ruber meaning red and is used to describe types of the mineral Corundum, that are of an orangey red to purplish red hue. This colour is created by the presence of the trace element chromium within the gemstone. Ruby crystals are formed in terminated hexagonal shapes, which are often tabular, and can be found within marble and basalt rocks. Ruby is the birthstone for the month of July and also the gemstone for the 40th wedding anniversary.
Ruby ranks 9 on moh’s scale of hardness, with only diamond ranking higher this makes it a very practical, and hard wearing gemstone to have in your jewellery collection, however it must be handled with care and can still be damaged if mistreated. To clean your ruby use warm soapy water and a soft toothbrush, once brushed, dry your Ruby using a soft lint free cloth. Ruby can also be cleaned in an ultrasonic or steam cleaner, however rubies which have been treated with cavity or fracture filling should only be cleaned with a damp cloth. Ruby is relatively tough and will withstand most household chemicals, and also the effects of strong heat and light, but like with any precious gemstone you should avoid these effects where possible. If you have a jewellery box, your Ruby jewellery should not be put together with other pieces otherwise general abrasion to the stones surface can cause scratches and this should be avoided.
Rubies are of the most important historical gemstones. The term ruby is mentioned four times in the Bible in reference to wisdom and beauty, and is called the most precious of the 12 stones created by God. Its deep red colour is synonymous with our deepest emotions love and anger. In Sanskrit ruby is named ratnaraj translating as the ‘king of gems’.
Ruby has a number of legends associated with it, Burmese warriors believed if you wore it in battle it would make you invincible, however it was not enough just to wear it, and so they would actually insert rubies in to their flesh so that it was part of them. The ancient Hindus believed if you offered fine rubies to the god Krishna they would be reborn as emperors. Wearing Ruby is also said to boost energy levels and self-esteem, it is a symbol of unconditional love, good fortune, and loyalty.
The largest mined Ruby is known as the ‘Liberty Bell’, it was sculpted to form a miniature version of the Liberty bell. It weighed in at 8,500 carats, and was mined in East Africa in the 1950s. Unfortunately it was stolen in a heist and is yet to be recovered. Other prized rubies include the ‘Sunrise Ruby’ which set records when it went to auction in 2015 and was sold for £19.1 million. It became the most expensive gemstone which was not a diamond. The ruby weighs 25.59 carats, was mined in Myanmar, and had a distinct and sought after pigeon blood appearance.
Generally, the most sought after colours of a Ruby are of a pure vibrant red to slightly purple red, and as such these stones are of a higher value. If the ruby is too orangey or purplish it will be of lesser value. The finest rubies cannot be too dark or light but must have the right balance of strength and saturation. If it is too light in colour, it will more than likely be termed as a pink sapphire; the GIA will only refer to the gem as a ruby if the red colour is the dominant hue on display. Historically the description of ‘pigeon blood’ has been given to rubies with a prized colour of red to purplish or pinkish red with a soft red fluorescent glow. A trade term such as ‘Burmese’ might also be given to describe a ruby with a fine colour, however the origin of the gem is not always consistent with its quality, and fine quality rubies can come from a number of locations.
With Ruby, some inclusions within the stone are very common, as inclusion free rubies are extremely rare. The important factor of clarity with ruby is how visible these inclusions are and this will help to determine the value of the gem, with heavily included rubies reducing both transparency and brightness, and potentially causing durability issues. Typical needle inclusions in ruby consist of fine rutile intersecting at angles to produce a clarity characteristic termed ‘silk’. Other zones of colour, small crystals, or finger print like inclusions may also be present. Ruby can sometimes benefit positively from these rutile ‘silk’ inclusions, whereby light within the stone is caused to scatter which creates an optical property called asterism or a star effect. These star rubies are normally cut as domed cabochon to best display this effect.
A ruby can be cut in to a variety of shapes. A cutter will often have the crystal shape of the ruby dictate the way in which it can be cut. As a result of this a popular choice of cut is oval or cushion, with larger stones often being cut this way. As the ruby rough is very valuable it is always the priority to conserve as much of the weight as possible. Ruby has an optical property known as pleochroism, and as a result shows two colours along different crystal directions, these are red to purplish red and orangey red. The cutter will where possible orient the table facet perpendicular to the long crystal direction so as to reduce the orangey red colouring. This may not always be possible as the priority for the cutter is foremost to maintain the weight of the gem.
Ruby can be found in a variety of sizes, however very large stones over 1 carats are very rare in fine qualities. Like diamond the price per carat can increase dramatically as you increase the carat weight and as such this is not a linear increase. Smaller rubies are readily available and can make fine accent stones in an eternity ring, or centre pieces in a pair of cluster earrings.
The most important locations and sources of gem quality ruby are Myanmar, Pakistan, Afghanistan, Thailand, Australia, Brazil, Columbia, India, Namibia, Japan, Tanzania, Vietnam and the USA.
It is commonly accepted that heat treatment has been used on Ruby to improve its colour and remove purple tinge and Silk. The stones are heated typically to a high temperature of around 1800 degrees, and this type of treatment is permanent. If the ruby has not been heat treated it should carry an independent laboratory certificate to state this, and us such its rarity and value will be higher. Other types of treatment on ruby include fracture filling whereby surface reaching fractures are filled with lead glass to lessen their visibility and increase the overall apparent transparency of the gem. This type of treatment is not generally accepted within the jewellery trade as it is unstable and can cause durability issues.