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Gemstone Spotlight: Ruby

Everything you need to know about July's birthstone!

The ruby is one of the four precious gemstones, along with diamond, emerald, and sapphire. In fact, it comes from the same mineral as sapphire, known as corundum! In its purest form, the mineral corundum is actually colorless; so what makes a ruby red? Trace elements that become part of the mineral's crystal structure cause the variations in color. In rubies specifically, Chromium will cause a ruby’s red color, which typically ranges from an orangey-red to a purpley-red. The finest color is a pure red with a hint of blue, commonly referred to as Pigeon’s Blood rubies. Corundum comes in many colors, but the others are generally classified as sapphires. The only exception is pink - pink corundum can be pink sapphire or pink ruby! The determination depends on the region of origin, color and opinion of a trained gemologist.

Ruby is a leading frontrunner in the gemstone world, and for good reason! Rubies can command the highest per-carat price of any colored stone. High-quality rubies that weigh over 10 carats can even sell for more than a similar sized diamond! Unlike diamonds, inclusions in rubies are to be expected and are generally well-tolerated. However, if large and prominent inclusions are located under the main table facet, they will greatly reduce the transparency, brilliance, and value of the stone. On the hardness scale, Ruby is a 9. This is slightly softer than the hardest which is a diamond (10), and matched with its counterpart, a sapphire! A 9 on the Mohs scale means this gemstone is very durable, extremely hard, and perfect for everyday wear.

Some of the most famous rubies include the 100.32 carat DeLong Ruby that is kept at the New York City Museum of Natural History, and the most expensive ruby ever sold: The Sunrise Ruby, which sold for more than $28.25 million and weighs 25.29cts.! Lastly, one of the most recognized ruby pieces is the Burmese Ruby Tiara handcrafted for Queen Elizabeth in 1973. This diamond and ruby crown is said to be valued over 7.5 million dollars!


  • In Sanskrit, ruby is ratnaraj, meaning the king of gems.
  • Ruby is the symbolic gemstone for the 15th and 40th anniversaries.
  • In honor of the fiftieth anniversary of The Wizard of Oz,  a jewelry company created a pair of actual Ruby Slippers using "about 25 carats of diamonds and 1,500 carats of rubies" - valued at $3 million, they are the most expensive shoes in the world!
  • Rubies are referenced four different times in the bible. The Bible associates these gems with beauty and wisdom.  
  • The largest mined Ruby is 8,500 carats and was stolen in Wilmington, Delaware in 2011. This Liberty Bell shaped Ruby includes 50 diamonds that represent each of the 50 states. After the heist, the thieves were prosecuted but the Liberty Bell Ruby has never been recovered!