Rubies can command the highest per-carat price of any colored stone. This makes ruby one of the most important gems in the colored stone market. In its purest form, the mineral corundum is colorless. Trace elements that become part of the mineral’s crystal structure cause variations in its color. Chromium is the trace element that causes ruby’s red color.
Birthstones & AnniversariesRuby is the birthstone for July and the gem for the 15th 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.
On May 12, 2015, a 25.59-carat ruby ring sold for $1,266,901 per carat, setting a new record at auction for a colored gemstone.
1.762 to 1.770
0.008 to 0.010
4.00 (+/- 0.05)
- Mohs Hardness: 9
There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.Learn More
Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.Learn More
Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.Learn More
Why We Love This Gemstone
Intense Red Glow
Fine ruby glows with intense red in sunlight thanks to red fluorescence, which intensifies its red color.
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.
The prices of fine-quality rubies have been breaking auction records.
Color is the most significant factor affecting a ruby’s value: Fine gems are a pure, vibrant red to slightly purplish red.
If a ruby's inclusions affect its transparency or brilliance they reduce the gem’s value significantly.
Rubies are commonly fashioned as mixed cuts, which have brilliant-cut crowns and step-cut pavilions.
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, gemological research, and the role of gems in history.
Ruby and Sapphire Production and Distribution: A Quarter Century of ChangeRussell Shor and Robert Weldon , Jan 1, 2009 Read Article
Identification and Durability of Lead Glass–Filled RubiesShane F. McClure, Christopher P. Smith, Wuyi Wang, and Matthew Hall , Apr 28, 2006 Read Article
Beryllium Diffusion of Ruby and SapphireJohn L. Emmett, Kenneth Scarratt, Shane F. McClure, Thomas Moses, Troy R. Douthit, Richard Hughes, Steven Novak, James E. Shigley,WuyiWang, Owen Bordelon, and Robert E. Kane , Jun 1, 2003 Read Article
The Ruby, Sapphire and Emerald Buying Guide: How to Identify, Evaluate and Select These Gems
Ruby & Sapphire