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The name “sapphire” can also apply to any corundum that’s not ruby red, another corundum variety.

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Madagascar Beauty

This 7.04-ct. oval sapphire is from a new source, the island Madagascar.

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Blue Velvet

Deep, intense, velvety blue describes this sapphire’s color.

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Best in Daylight

Blue sapphire looks best in daylight and fluorescent light.

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Spindle Shape

This spindle-shaped crystal from Sri Lanka weighs 70.10-cts.

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Color Zoning

Blue color distribution in sapphire crystals is often uneven.

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There is a second sapphire crystal growing into the larger one.

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About Sapphire

About Sapphire

Besides blue sapphire and ruby, the corundum family also includes so-called “fancy sapphires.” They come in violet, green, yellow, orange, pink, purple, and intermediate hues. Some stones exhibit the phenomenon known as color change, most often going from blue in daylight or fluorescent lighting to purple under incandescent light. Sapphires can even be gray, black, or brown.

Sapphire Description

Sapphire History and Lore

Sapphire Journey

Birthstones & Anniversaries

Sapphire is the birthstone for September and the gem of the 5th and 45th anniversaries.


Intensely saturated and velvety, rare sapphires from Kashmir set the standard for blue.

Royal Blue

The world’s most famous engagement ring: Kate Middleton’s and Princess Diana’s sapphire.


A rare and valuable pinkish-orange sapphire named from the Sinhalese for lotus blossom.


  • Mineral: Corundum
  • Chemistry: Al2O3
  • Color: Every color but red
  • Refractive index: 1.762 to 1.770
  • Birefringence: 0.008 to 0.010
  • Specific gravity: 4.00
  • Mohs Hardness: 9


There are a number of processes used to alter the color, apparent clarity, or 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 manmade materials or by natural materials chosen by man to impersonate a particular gem.

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Why We Love This Gemstone

Vivid And Saturated

Sapphire’s blue can be vivid and saturated, like it’s lit from within.


It’s so durable, synthetic sapphire is used for the windows of supermarket scanners and spacecraft.

Delicate Silk

Sapphire often contains delicate intersecting needles of rutile that gemologists call silk.

Quality Factors

Each color of sapphire has its own quality variations.


quality factors

Sapphires come in a variety of colors. Preferred sapphires have strong to vivid color saturation, regardless of hue.


quality factors

Blue sapphires typically have some inclusions, but they generally have better clarity than rubies.


quality factors

Sapphire is often cut with a brilliant pattern on the crown and a step cut pattern on the pavilion.

Carat Weight

quality factors

Blue sapphires range in size, and large blue sapphires are more readily available than large rubies.

Sapphire Quality Factors: The Comprehensive Guide


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

Suite containing over 36 carats of Yogo sapphire

Gemological Characterization of Sapphires from Yogo Gulch, Montana

Nathan D. Renfro, Aaron C. Palke, and Richard B. Berg , Aug 6, 2018 Read Article
Paula Crevoshay’s “Yogo Columbine” sapphire pendant

The Role of Silicon in the Color of Gem Corundum

John L. Emmett, Jennifer Stone-Sundberg, Yunbin Guan, and Ziyin Sun , May 7, 2017 Read Article
Montana sapphires after two rounds of heating

Big Sky Country Sapphire: Visiting Montana’s Alluvial Deposits

Tao Hsu, Andrew Lucas, Robert E. Kane, Shane McClure, and Nathan Renfro , Aug 7, 2017 Read Article
Sapphire cabochon displaying asterism.

Unique Star Sapphire with Transparent Core

Yusuke Katsurada , Aug 9, 2018 Read Article