Everything You Need to Know About Sapphires

January 9th, 2023

Consider choosing a stunning sapphire piece when shopping for jewelry as a gift or for everyday wear. While sapphires are known for their striking blue color, they also have unique features that make them vibrant, durable, and dazzling pieces for your jewelry collection. 

What is a Sapphire?

Sapphire is a precious colored gemstone and one of two varieties of the mineral corundum. Sapphires are formed in igneous and metamorphic rock deposits, including granite, gneiss, schist, and nepheline syenite. However, they can also be found in alluvium (clay, sand, or silt deposits left by floodwaters).

 

While royal blue sapphires are the most well-known type, there are trace amounts of elements that can affect their color. Classic blue sapphires get their hue from iron and titanium, while some sapphires are turned pink by adding chromium. High iron levels can create green or yellow sapphires, and the combination of iron and chromium results in a yellow-orange sapphire. These colorful sapphires are referred to as “fancy sapphires.”

Where are Sapphires Mined? 

Sapphires are found in many locations around the globe, including Australia, Cambodia, Cameroon, Sri Lanka, and China. Montana is the only location where sapphires are commercially mined in the United States. 

Sapphires can also be created synthetically in laboratories. Lab-grown sapphires are physically identical to natural sapphires to the naked eye. Both types of sapphires are made using the same base mineral, corundum; however, while natural sapphires are formed over millions of years, lab-grown sapphires can be fabricated in as little as a few weeks.

Because synthetic sapphires are easier to produce, they are more affordable. They are more ethical since they aren’t sourced from socio-economically disadvantaged areas. They are also more sustainable because they do not disrupt local habitats or produce significant industrial waste or carbon emissions. 

Synthetic sapphires can be created through two general processes: melting and solution. 

  • Melting processes like flame fusion, the Verneuil process, and the Czochralski process start with aluminum oxide (corundum) powder. The powder is melted using heat or radio waves to form a solid teardrop-shaped boule. This is then dipped in seed crystals from various minerals to achieve different colors. 

 

  • The solution process uses a method called hydrothermal synthesis, which closely mimics the natural sapphire formation process. It starts with a seed crystal that is exposed to a mineral-rich solution. As the pressure rises in the hydrothermal vessel, the minerals deposit on the seed crystal to form a sapphire.

Sapphire Hardness, Toughness, and Stability

When purchasing sapphire jewelry, consider hardness, toughness, and stability. This ensures that your piece can withstand daily wear and tear. 

Hardness refers to the gemstone’s ability to resist wear and abrasion. Because sapphires are made from corundum, they are one of the hardest-known gemstones, second only to diamonds. Gemstone hardness is rated according to the Mohs Hardness scale, with sapphires scoring a 9 out of 10

Toughness measures the force required to separate two surfaces of a gemstone along a specific crystallographic plane. Sapphires have a moderate toughness of around 600, meaning they aren’t likely to chip or shatter. 

They do not display any cleavage, which refers to the tendency for a gemstone to break when it is struck, so they are suitable for everyday wear. However, sapphires can be damaged by mild acids such as lemon juice, so avoid wearing sapphire jewelry when preparing food or cleaning.

How Are Sapphires Treated?

Gemstones are treated to enhance their physical properties, which can increase their value. Some common sapphire treatments include:

  • Heat Treatment

Exposing gemstones to 400°C temperatures increases their color and clarity. Heating is typically used to lighten or darken the color of a sapphire and intensify the blue hue. 

  • Lattice Diffusion

Lattice diffusion diffuses an element into a gemstone to change its color artificially. Diffusion treatments have varying degrees of treated-color penetration. In some treatments, the whole stone’s color is altered, while in others, there is shallow color penetration.

Gemstones may also be fracture-filled to fill any inconsistent surfaces. Fracture-filled stones are typically filled with high lead-content glass, which causes them to be more easily damaged by mildly acidic substances. Very low quality stones may also be chemically-dyed to make them more appealing to consumers.

Assessing Sapphire Quality

Before buying a sapphire, have a professional assess the quality of the gemstone to ensure that you find jewelry that meets your expectations. Whether you’re shopping for sapphire birthstone jewelry as a gift, a charm bracelet, or a sapphire jewelry set for everyday wear, focus on the four critical aspects of sapphire quality: color, cut, clarity, and carat.

Four different colored sapphires on a neutral background
  • Color

Color is the most important quality factor and has the greatest influence on the overall value of a sapphire. The more intense and consistent the color is on a gem, the more valuable it is. Medium and medium dark tones of sapphires are more valuable than most lighter shades. These sapphire colors are rarer and command a higher price per carat weight. 

Fancy sapphires, such as rare orange-pink padparadscha sapphires, are also stones that increase in value based on their vibrancy in color. Deeply saturated purple and pink sapphires are more valuable than light sapphires. 

In addition to solid-colored sapphires, you can also find spectacular parti sapphires. These multi-color or two-tone sapphires result from color-zoning caused by uneven temperature changes or distribution of trace elements during the rock’s formation. Parti sapphires display two or three colors simultaneously, such as yellow and green or blue, purple, and lavender.  

Some sapphires that contain vanadium deposits have color-changing properties when exposed to different light sources. This is known as pleochroism and is due to the crystal structure absorbing a particular wavelength depending on the direction of the light vibration passing through the gem.

  • Cut 

Gem cutting refers to the shape and arrangement of stone’s facets. Cutting transforms the rough stone into a glittering gemstone that can be used in jewelry making. 

 

Teardrop-shaped gems are often used to make a beautiful sapphire necklace. Simple oval or round cuts can create dazzling gemstone earrings, while a classic princess cut can create stunning sapphire rings.

  • Clarity

Gemstones with high clarity are free of materials trapped inside the gem, fractures, and surface imperfections. Sapphires generally have higher clarity than similar stones, such as rubies, but sapphires with very high purity and clarity are extremely rare and valuable.

Clarity ratings can range from VVS (very, very small inclusions) to SI (small inclusions) and I (included) grades. The higher the clarity grading, the more valuable the stone.

Sapphire and white gold ring and earrings with sapphire gemstones
  • Carat

A carat refers to a diamond or gemstone’s size and weight, which correlates to the cost. Blue sapphire jewelry ranges from a few points to hundreds of carats. However, the majority of blue sapphires are less than 5.0 carats. 

The sapphire’s carat weight, combined with the carat weight of other gemstones used to make jewelry pieces, affects the price. Other factors that influence the price of a piece of jewelry include the purity of the gold used in the piece (measured in karats) and the designer’s brand name.

Sapphire Care and Cleaning

Since sapphires are highly durable, minimal care is necessary to maintain the quality of the gemstone. Sapphires can be cleaned with warm soapy water or an ultrasonic or steam cleaner. However, you should only use a damp cloth to clean fracture-filled or dyed material.

Protect Your Sapphire Jewelry with BriteCo™

Stunning sapphire jewelry can be an investment, so make sure your jewelry is protected with help from our team at BriteCo.  We provide affordable insurance for engagement rings, fine jewelry, and luxury watches.

You can receive a free quote in less than two minutes by answering a few simple questions on your phone. Visit our team at BriteCo in-store or contact us online.

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About the Author

Dustin Lemick is the Founder and CEO of BriteCo and a third-generation jeweler with over thirteen years of retail jewelry experience. He holds a Graduate Gemologist degree from the Gemological Institute of America (GIA) and has in-depth knowledge and expertise in appraisal systems, diamond and gemstone markets, retail pricing models, insurance replacement models, and jewelry quotation pricing systems.
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