Ruby red gemstone

Ruby is a red variety of the mineral corundum, renowned for its hardness and intense color, making it one of the world's most valuable gemstones.

About this subject

Ruby is a red variety of the mineral corundum (aluminum oxide), colored by chromium impurities. With a hardness of 9 on the Mohs scale, it is the second-hardest gem after diamond. Natural rubies of large size and high clarity are extremely rare.

Historically, ruby has been called the "king of gems" across many cultures. In ancient India, it was believed to grant invincibility. In Burma (modern Myanmar), warriors wore them as talismans. The Mogok region in Myanmar is legendary for producing "pigeon's blood" rubies, the most prized color.

Today, the main producers are Myanmar, Thailand, Mozambique, Sri Lanka, and Madagascar. Mozambique rubies have gained prominence in recent decades. Most commercial rubies undergo heat treatment to improve color and clarity, a market-accepted practice when disclosed.

Interestingly, synthetic rubies have been produced since the 19th century via flame fusion (Verneuil) and are used in watchmaking and lasers. Star rubies display asterism due to rutile inclusions. In value, untreated natural rubies over 5 carats can surpass diamonds of equal size in per-carat price.

Frequently Asked Questions

What is the difference between ruby and sapphire?

Both are the same mineral, corundum. The difference lies in color: rubies are red (due to chromium), while sapphires are any other color (blue, pink, yellow, etc.). Red sapphires do not exist; they are classified as rubies.

Where are the best rubies found?

The most famous rubies come from the Mogok region in Myanmar (Burma), known for 'pigeon's blood' color. Mozambique, Thailand, and Sri Lanka also produce high-quality rubies.

How can you tell if a ruby is real?

Identification requires gemological tests such as refractometry, inclusion analysis, and fluorescence. Natural rubies usually have inclusions, while synthetics can be very clean. Be suspicious of very low prices and prefer certificates from reputable laboratories.