July Birthstone – Ruby
Ruby is the July birthstone – and it’s one of the most coveted of gems. Called the “king of gems” in ancient India, today it can get the highest price per-carat of any other coloured stone. Here’s what you need to know about this beautiful gem.
Ruby is a variety of the mineral corundum (Sapphires also belong to the corundum family) that contains trace amounts of the element chromium, which causes its colour. The more chromium present, the stronger the colour red. Chromium can also cause red fluorescence, which adds to the intensity of the colour.
Burma historically produced the finest ruby material, famous for its deep blood-red colour with purplish hues. These Burmese Rubies, also called Pigeon’s Blood Rubies, command a premium over brownish or orange-tinged varieties from other regions of the country. Other ruby deposits exist in Vietnam, Thailand, India, parts of the Middle East, East Africa and even the United States.
Due to its deep red colour, ruby has long been associated with the life force and vitality of blood. It is believed to amplify energy, heighten awareness, promote courage and bring success in wealth, love and battle. Symbolic of passion, protection and prosperity, the ruby has been revered since ancient times.
Rubies have been particularly prized in Asian countries. Records suggest that rubies were traded along China’s North Silk Road as early as 200 B.C. Chinese noblemen adorned their armour with rubies because they believed the gem would grant protection. They also buried rubies beneath building foundations to secure good fortune.
Though ruby has a long history, it wasn’t recognised as a variety of corundum until 1800. Prior to that, red spinel, tourmaline, and garnet were also believed to be ruby. Even the Black Ruby, one of the famed crown jewels of England, was considered one of the largest cut rubies until determined to be spinel.
Imitation ruby dates back as far as Roman times, though it wasn’t synthesised until the early 1900s. The red fluorescence power of ruby helped build the first working laser in 1960. Rubies—both natural and synthetic—are still used to make lasers, as well as watches and medical instruments.
How to Buy Ruby
Popular since ancient times, these precious gems are said to rouse the senses, amplify positive energy and guarantee health, wisdom, wealth and success in love.
Colour – colour is the most important quality factor for the July birthstone. The finest rubies have a pure, vibrant red to slightly purplish red colour. A colour that’s too orangey or too purplish is considered less desirable. The highest-quality rubies have vivid colour saturation that is not too dark.
Clarity – People in the trade expect rubies to have at least some inclusions, because inclusion-free rubies are rare. The impact of inclusions on the value of a stone depends on their visibility. Obvious inclusions or inclusions that reduce transparency or brightness can lower a ruby’s value. All natural rubies contain imperfections, like rutile inclusions called “silk.” These can actually increase the value of ruby (when displaying a rare cat’s eye or star effect) and are often used to determine a gem’s authenticity.
Cut – A ruby’s crystal shape dictates its suitability for certain cuts. Ruby crystals often have a flat tabular hexagonal shape, but crystals from some sources may be elongate.
Carat – Rubies are available in a wide range of sizes, but fine-quality rubies over a carat are rare and, not surprisingly, very expensive.
Ruby Treatments, Care & Cleaning
Using warm soapy water is a safe option to clean a ruby. Ultrasonic and steam cleaners are usually safe for untreated, heat-treated and lattice diffusion–treated stones. Fracture-filled, cavity-filled or dyed stones should only be cleaned with a damp cloth.
Rubies are often heat treated to remove purplish colouration, leaving a purer red. The process can also remove “silk” (minute needle-like inclusions) that can cause a gem to appear lighter in tone and be more opaque. The trade typically accepts heat treatment to enhance colour, as the treatment is stable to normal conditions of wear and care.
Lattice diffusion is a technique whereby heat and chemicals are used to diffuse a specific element into a gem to change its colour. This treatment, too, is typically stable to normal wear and care.
Fracture filling is when a substance is introduced into surface-reaching fissures to make them less visible and thus improve the gem’s appearance. Common fillers include glass and glass-like substances, polymers and resins, and oils.
A high-lead-content glass is often used to fill fractures in rubies and thus improve their apparent clarity. There are many of these glass-filled rubies in the market, and in some cases the glass literally holds together a highly fractured gem. The glass can be damaged through contact with a variety of chemicals. Even relatively mild substances like concentrated lemon juice can etch the filler.
Dyeing with coloured oils and filling small surface fissures with epoxies are other treatments. However, they are not permanent. These treatments need special care.
Always ask if your ruby has been treated before you buy as treatments affect a gemstone’s perceived value. A GIA Identification Report is important in identifying if a stone is natural or synthetic and whether it has been treated in any fashion.