Ruby Guide
What is Ruby
Ruby is one of the most important gemstones in the world and belongs to the mineral species corundum, the same mineral family as sapphire.
Only the red variety of corundum is classified as ruby. All other colors of corundum are classified as sapphire.
Ruby has been treasured for thousands of years for its vivid color, rarity, and durability. Throughout history it has symbolized power, vitality, and passion, making it one of the most prestigious gemstones used in fine jewelry.
Because of its exceptional hardness and intense color, ruby continues to be one of the most desirable gemstones in the modern jewelry market.
Ruby Formation
Rubies form deep within the Earth's crust under high temperatures and pressure.
They develop primarily in metamorphic rocks such as marble or within basaltic environments. During the formation process, trace elements such as chromium enter the crystal structure of corundum and produce the characteristic red color.
Over time geological processes bring ruby-bearing rocks closer to the Earth's surface, where the gemstones can later be mined.
Chemical Composition and Crystal Structure
Ruby has the chemical composition Al₂O₃ (aluminum oxide).
It crystallizes in the trigonal crystal system, forming hexagonal barrel-shaped crystals.
The red color of ruby is caused by the presence of chromium within the crystal lattice. This element also produces the fluorescence that gives some rubies their vivid glow under certain lighting conditions.
Hardness and Durability
Ruby ranks 9 on the Mohs hardness scale, making it one of the hardest natural gemstones used in jewelry.
This durability makes ruby suitable for rings and everyday jewelry pieces. Only diamond ranks higher in hardness.
Despite its hardness, ruby can still fracture under strong impact, which is why careful cutting and protective settings are important.
Optical Properties
Ruby has several optical characteristics that contribute to its beauty.
Important properties include:
• Refractive Index: approximately 1.76–1.77
• Luster: vitreous
• Pleochroism: visible red color variations depending on viewing angle
High-quality rubies display vivid color saturation and strong internal brilliance.
Ruby Colors and Varieties
Rubies range in color from pinkish red to deep purplish red.
The most prized color is often described as “pigeon blood red”, a vivid red with slight blue undertones and strong saturation.
Some rubies may also display the phenomenon known as asterism, where a star-shaped pattern appears on the surface of the stone when cut as a cabochon.
These stones are known as star rubies.
Main Ruby Sources
Important ruby sources include:
• Myanmar (Burma)
• Mozambique
• Thailand
• Sri Lanka
• Madagascar
• Vietnam
Myanmar has historically produced some of the most famous rubies, although Mozambique has become one of the most important modern sources.
Ruby in History
Rubies have been admired since ancient times.
In many cultures ruby was considered the “king of gemstones” because of its deep red color and rarity. Ancient rulers and warriors believed ruby provided protection and strength.
Rubies have appeared in royal jewelry collections across Asia, the Middle East, and Europe for centuries.
Ruby Symbolism
Ruby symbolism often includes meanings such as:
• vitality
• courage
• passion
• strength
• protection
Its rich red color has historically been associated with life force and emotional intensity.
Ruby in Modern Jewelry
Ruby remains one of the most important gemstones in fine jewelry today.
It is frequently used in high-jewelry creations and statement pieces. Rubies are often paired with diamonds or set in yellow or white gold to enhance their color and brilliance.
Because of their rarity, fine rubies can command very high prices in the gemstone market.
Ruby and Meaningful Jewelry
Beyond its beauty, ruby carries strong emotional symbolism.
Many people choose ruby jewelry to represent energy, determination, and personal strength. Because of these associations, ruby is often selected for important life milestones or meaningful gifts.
Within the DONYDO philosophy, ruby reflects vitality and inner power.
Treatments and Enhancements
Most rubies on the market undergo heat treatment to enhance color and clarity.
Other treatments such as fracture filling may also occur in some stones.
Professional gemological laboratories identify and disclose treatments during certification.
Care and Maintenance
Ruby jewelry is relatively easy to maintain.
Recommended care includes:
• cleaning with mild soap and warm water
• avoiding strong chemicals
• storing separately from softer gemstones
With proper care, ruby jewelry can last for generations.
Related Gemstone Guides
Sapphire Guide
Emerald Guide
Diamond Guide
Tourmaline Guide
Spinel Guide
Garnet Guide
Lab-Grown Diamond Guide