Ruby: Meaning, Symbolic Properties, Care

What is ruby?

Ruby is the red variety of corundum, a mineral made of aluminium oxide (Al2O3). Pure corundum is colourless; when it contains a little chromium, it turns red, and it is then called ruby. The same mineral in blue, yellow, pink or green is called sapphire. The word "ruby" comes from the Latin ruber, "red".

With a Mohs hardness of 9 (on a scale from 1 to 10), it is one of the hardest natural materials, after diamond. This durability, together with its brilliant colour, explains its status as a precious stone, on a par with diamond, sapphire and emerald.

Historic sources of quality ruby are in Myanmar (the Mogok valley and the Mong Hsu area), in Mozambique (the Montepuez mine, worked since the late 2000s), and also in Thailand, Madagascar and Tanzania. The finest rubies, in a vivid, saturated red, are called "pigeon's blood" in the trade. Some rubies contain fine needles of rutile (the "silk") that produce a star effect, called asterism, on cabochons.

History and anecdotes

Ruby has long been associated with power and royalty. In Indian tradition, it bears the title "king of precious stones". In Europe too, red gems adorn crowns. But be careful: a great "ruby" of history is sometimes something else. The Black Prince's Ruby of the British imperial crown is in fact a spinel, a different red stone. For centuries, the two could not be told apart.

Ruby also has a scientific history: at the start of the 20th century, the French chemist Auguste Verneuil developed a method for making synthetic rubies, and a ruby crystal was used in 1960 to build the first laser, made by Theodore Maiman.

Traditional symbolism

Red like blood and fire, ruby is traditionally associated with passion, vitality and courage. It is also cited for confidence and nobility of spirit. In both Europe and Asia, it evokes wealth and power.

These meanings are beliefs and symbols, not demonstrated effects. A ruby brings neither health nor fortune; it remains above all a rare precious stone.

Traditional correspondences

See also courage.

How to use it

• In jewellery: ring, pendant or earrings. Its hardness of 9 makes it one of the stones best suited to a ring worn every day.
• As beads or cabochons: rough ruby or cabochons of modest quality, often opaque, are available and more affordable than faceted stones.
• As a gift: a July jewel, or a wedding anniversary gift (ruby is the traditional stone for the 40th anniversary).

See the guide to gemstone jewellery.

Cleaning and cleansing

• Routine cleaning: lukewarm water, mild soap and a soft brush. An uncracked ruby is very durable.
• Lead-glass-filled ruby: if fissures have been filled with lead glass, avoid ultrasonic cleaners, heat and all acidic or chemical products (lemon juice, descaler) that can damage the filling. An old or inexpensive piece may be affected.
• Impacts: hardness does not protect against a violent blow; rubies sometimes have internal fractures.
• Sunlight: harmless for a natural ruby.
• Symbolic cleansing: incense smoke, moonlight. See the guide to cleansing and recharging your stones.

Recognising a real ruby and avoiding confusion

Ruby is one of the most treated and imitated stones. Almost all rubies on the market have undergone heating, which the trade accepts if it is declared; filling with lead glass improves the appearance of very fissured stones but weakens the piece. Synthetic rubies also exist, made in a laboratory: they are real rubies chemically, but manufactured, and they must be sold as such.

• Spinel, garnet, red tourmaline, glass: these are wrongly sold as ruby. Spinel (see spinel) is often mistaken for ruby.
• Ruby-zoisite: a green rock with scattered rubies, also called anyolite; it is not a jewellery ruby, see ruby-zoisite.
• "Reconstructed" ruby: a stone made from fragments; this must be stated on the listing.

In costume jewellery, "ruby" often refers to a different material. Only a laboratory can guarantee the origin and treatments of a precious stone; for an important purchase, ask for a certificate. Our guide to choosing and caring for your stones explains these points in detail.

How to choose your ruby

The key criteria are colour (a vivid red, neither too pink nor too dark), transparency, inclusions and size. Gem-quality rubies are expensive and increasingly rare in large sizes, whereas opaque rubies or cabochons are more affordable. Always ask about treatments.

It pairs well with carnelian and garnet within the family of red stones. See the jewellery section.

Frequently asked questions

Also read

The meanings mentioned belong to tradition and symbolism. They are neither promises of results nor medical advice. Back to Guide to stones.