July ~ Month of Ruby

July ~ Month of Ruby

History and Lore

Corundum Specimen Smithsonian Collection

Ruby is the red variety of the mineral corundum, colored by the element chromium.  Chromium causes fluorescence, which makes rubies glow like a fire from within. The name “ruby” comes from rubeus, the Latin word for red. In ancient Sanskrit, ruby translated to ratnaraj, which meant “king of precious stones.” These fiery gems have been treasured throughout history for their color and vitality. Rubies are mentioned four times in the Bible, in association with attributes like beauty and wisdom.

Mughal Dynasty (1526 – 1858)
Source: Smithsonian Collection

Rubies have been particularly prized in Asian countries. Records suggest that rubies were traded along China’s North Silk Road as early as 200 BC. Chinese noblemen adorned their armor with rubies because they believed the gem would grant protection. Ancient Hindus believed that those who offered fine rubies to the god Krishna were granted rebirth as emperors.

UK State Imperial Crown
Source: Tower of London

Though ruby has a long history, it wasn’t recognized as a variety of corundum until 1800. Prior to that, red spinel, tourmaline, and garnet were also believed to be ruby. Even the Black Prince’s Ruby, one of the famed crown jewels of England, was considered one of the largest cut rubies until determined to be spinel. As with many royal gemstones, there is a long history behind this 170 carat red gemstone, including mysterious disease and death attributed to Sultan Abu Said of Granada’s Curse. More at Crown Jewel History.

Ruby Gemstone Sources

Carmen Lucia Burmese Ruby
Smithsonian Collection

Burma’s Mogok Valley historically (since 600 A.D.) produced the finest ruby material, famous for its deep blood-red color with purplish hues. These Burmese Rubies, also called Pigeon’s Blood Rubies, command a premium over brownish or orange-tinged varieties from other regions.

3.56ct Thai Cushion Cut Ruby Smithsonian Collection

The Mong Hsu region of Myanmar began producing rubies in the ‘90s after discovering that heat treatment improved the color saturation. Other ruby deposits exist in Vietnam, Thailand, India, parts of the Middle East, Kenya and Tanzania, Africa, and even the United States.

Rockland Ruby Mine in Kenya, Source: GIA.org

Some Famous Rubies

Rosser Reeves Star Ruby

Rosser Reeves Star Ruby, Sri Lanka Source: Smithsonian Collection

The Rosser Reeves Star Ruby might be the largest and finest star ruby in the world. The star forms when titanium atoms are trapped within the growing corundum crystal. When properly cut, en cabochon, light reflecting off the three sets of needles produces a six-rayed star. This phenomenon is called asterism. The Rosser Reeves Star Ruby is from Sri Lanka, but its early history is not known. When it was purchased by a gem dealer in London in the late 1950s, the ruby weighed 140 carats, but it was recut to 138.72cts to center the star. Rosser Reeves, whose name it now bears, carried it around as a lucky stone. He donated it to the Smithsonian in 1965.

The Crimson Flame Source: The Jewellery Editor

The Crimson Flame

This exceptional Burmese ruby-and-diamond ring of 15.04 carats, known as the Crimson Flame, sold at Christie’s Hong Kong in 2015 for just under $18.3 million, or $1.22 million per carat. Its prized pigeon-blood red color and near perfect crystallization make it one of the most extraordinary rubies in the world.


Tough and durable, ruby measures 9 on the Mohs scaleDiamond is the only natural gemstone harder than ruby. Paradoxically, chromium is also what makes this gem scarce because it can cause cracks and fissures. Few rubies actually grow large enough to crystallize into fine quality gems, and these can bring even higher prices than diamonds.

Clean rubies with warm soapy water.  Gently scrub the stone with the help of a soft-bristled toothbrush. Rinse in clean water and wipe with a lint-free soft cotton cloth. Do not use chemicals such as chlorine, bleach, ammonia, acids, or alkalis, as these can etch a ruby’s surface, and/or affect color-enhanced stones.

Ruby’s strength and red fluorescence make it valuable for applications beyond jewelry. Both natural and synthetic rubies are used in watchmaking, medical instruments, and lasers.

Ruby is the birthstone for July and the gem for the 15th and 40th anniversaries.

Ruby Faceted Oval Cabochons
Assorted Free-Form Rubies

Please visit the SFJS showroom to see our collection of ruby gems and cabochons. We also carry a variety of findings that are perfect for creating custom jewelry for that special someone!

SFJS thanks the GIA , AGS , and Smithsonian Institution for their source information on Rubies and Corundum.

This post is intended to be educational, as a service to SFJS customers. Sources have been cited to give proper credit where possible. No copyright infringement is intentional by SFJS or its employees.