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Ruby is the most valuable variety of the corundum mineral species, which also includes sapphire.

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Fine Mogok Ruby

This fine 2.58-ct. ruby is from Myanmar’s classic Mogok deposit.

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Ruby’s extraordinary red colour is caused by traces of chromium.

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Mixed Cut

Like many fine rubies, this example is fashioned as a mixed cut.

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Calcite Matrix

These exceptional ruby crystals on calcite are from Mogok, Myanmar.

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Origin In Marble

The snow white calcite matrix hints at the ruby crystal’s origin in marble.

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Ruby Crystal

The characteristic form of this ruby crystal allows it to be recognised.

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About Ruby

Rubies can command the highest per-carat price of any coloured stone. This makes ruby one of the most important gems in the coloured stone market. In its purest form, the mineral corundum is colourless. Trace elements that become part of the mineral’s crystal structure cause variations in its colour. Chromium is the trace element that causes ruby’s red colour.

Ruby Description Ruby History and Lore Ruby Journey

Birthstones & Anniversaries

Ruby is the birthstone for July and the gem for the 15th (in the U.S.) and 40th anniversaries.


In Sanskrit, ruby is ratnaraj, meaning the king of gems.


Myanmar’s legendary valley of rubies; the source of many of the world’s most fabulous gems.

$32.4 million (£20.7 million)

On 12 May 2015, a 25.59 carat ruby ring sold for $1,266,901 (£810, 690) per carat, setting a new record at auction for a coloured gemstone.


  • Mineral: Corundum
    Chemical composition

Where It's Found



There are a number of processes used to alter the colour or apparent clarity, or to improve the durability of gems.

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Some gemstones have synthetic counterparts that have essentially the same chemical, physical and optical properties, but are grown by man in a laboratory.

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Any gem can be imitated – sometimes by man-made materials or by natural materials chosen by man to impersonate a particular gem.

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gem love

Why We Love This Gemstone

Intense Red Glow

Fine ruby glows with intense red in sunlight thanks to red fluorescence, which intensifies its red colour.

First laser

The first laser was created in1960 using the red fluorescence light emitted by ruby.


Chromium causes ruby's red. Gemologists consider it the "rock star" of trace elements.

Quality Factors

The prices of fine-quality rubies have been breaking auction records.


quality factors

Colour is the most significant factor affecting a ruby’s value: Fine gems are a pure, vibrant red to slightly purplish red.


quality factors

If a ruby's inclusions affect its transparency or brilliance they reduce the gem’s value significantly.


quality factors

Rubies are commonly fashioned as mixed cuts, which have brilliant-cut crowns and step-cut pavilions.

Carat Weight

quality factors

Fine-quality rubies over one carat are very rare and price goes up significantly as size increases.

Ruby Quality Factors: The Comprehensive Guide


Explore sources, gemmological research and the role of gems in history.

Ruby and Sapphire Production and Distribution: A Quarter Century of Change

Russell Shor and Robert Weldon Read more in English

Identification and Durability of Lead Glass–Filled Rubies

Shane F. McClure, Christopher P. Smith, Wuyi Wang, and Matthew Hall Read more in English

Rubies and Sapphires from Winza, Central Tanzania

Dietmar Schwarz, et al. Read more in English

Beryllium Diffusion of Ruby and Sapphire

John L. Emmett, et al. , Jun 1, 2003 Read more in English