Sapphire is a gemstone from the corundum mineral family, most famous in the color sapphire blue. However, the gemstone comes in a spectrum of colors, making it a desirable choice for jewelry. There’s a lot to learn about this famous jewel, like the role minerals play in color, how origin influences value, and the gem’s vibrant colors and symbolism.
Famous for their rich color, sapphire gemstones have desirable luster, durability, and hardness. Next to diamonds, sapphires are the hardest gem-quality mineral in the world. When we talk about sapphires, we’re most often referring to the gemstone’s signature blue color. That said, the various types of sapphires span the rainbow, which we’ll elaborate on in greater detail later.
We’ve compiled all of the pertinent sapphire information in this extensive guide to give you a comprehensive overview of the gem’s characteristics, meaning, origins, colors, and value.
Sapphire is the famous gem from the corundum mineral class, alongside its sister gem, ruby. However, pure corundum is colorless. It’s the presence of trace impurities in the stone’s chemical structure that influence each gem’s color. Otherwise, all sapphires would be colorless.
Known for its hardness and durability, sapphires are most commonly used in jewelry designs because, in addition to being gorgeous, they’re built to last through daily wear and tear. In fact, many people choose to wear sapphire engagement rings, but the stone also beautifully compliments earrings, necklaces, pendants, and bracelets.
Blue is the true color of sapphire, which is also called sapphire blue, blue sapphire, Kashmir sapphire and cornflower blue Sapphire. The Sapphire gemstone is a precious gem, along with rubies, emeralds, and diamonds.
Sapphire is the official September birthstone, and zodiac stone for Taurus (April 21-May 20), Virgo (Aug 24-Sept 22), and Libra (Sept 23-Oct 23).
The average sapphire carat weight is around 1 carat, however, there’s no cap on their size, as demonstrated by one of the largest sapphires in the world: the 423-carat Logan sapphire.
Below, we’ll outline the important details of sapphire composition.
Sapphires chemical formula: Al2O3
Mineral group: Corundum
Sapphire hardness on the Mohs Scale: 9
Color: Blue, Green, Purple, Orange, Yellow, Pink, White, Colorless, Brown, Gray, Black, Padparadscha, Color-Changing
Transparency: Transparent to opaque
Refractive Index: 1.76-1.77
Double refraction: .0008
Specific Gravity: 3.99-4.1
Cleavage: None, but some show parting along vulnerable areas
Crystal form: Hexagonal pyramids and tabloid shapes
With a firmer grasp of sapphire gemology, let’s dive into sapphire cultural meaning and historical significance.
There’s a reason why this classic stone is regaled by royalty and treasured worldwide. Sapphires have a sacred importance and significant meaning which heightens their allure. The gem’s name is derived from the Latin word sapphiru, meaning blue.
During the middle ages, sapphires were used to preserve chastity, sniff out treachery, and protect from natural diseases. Clergymen wore sapphires to represent Heaven, enemies used the gems as bargaining chips, and oracles used them as a conduit to prophesy the future.
The sapphire stone meaning represents celestial wisdom and divinity spanning cultures — from Hebrew lore to Greek mythology to Buddhist enlightenment.
Regal blue sapphires honor royalty and are engraved in ancient and medieval history. Sapphires are especially popular placed in rings for monarchs and notable figures both historic and modern.
Princess Diana’s famous 12-carat sapphire ring (worth a cool $500k) was passed down to the Duchess of Cambridge, Kate Middleton.
Sapphire is both a gemstone and color reference, with the earliest records depicting sapphire as a color tracing back to 1430.
If you’ve ever heard of a non-blue sapphire referred to as “Oriental,” it’s because for a time, these corundum gems were referred to as an entirely different gemstone. A perfect example is “Oriental Emerald” which is really just green sapphire. As you can imagine, this was a misleading practice making it difficult to distinguish emeralds from sapphires.
In the Book of Ezekiel in the Old Testament, God is depicted at the seat of a sapphire throne in Heaven.
The popular gin brand, Bombay Sapphire, has a sapphire-hued bottle.
In Ancient Greece, sapphire was associated with the Olympian god, Apollo.
Blue sapphires represent the planet Venus and its assigned weekday, Friday.
Sapphire is a popular girl’s name, meaning “blue” in Hebrew.
American novelist and poet Ramona Lofton wrote under the pen name, Sapphire.
The single most crucial factor of valuing a sapphire stone is its color. Color isn’t defined solely as blue, green, or yellow. To get an in-depth understanding of a sapphire’s color, we need to look at hue, saturation, and tone.
Hue is the gemstone’s color, i.e. a blue sapphire has a blue hue.
Saturation refers to the gem’s color purity on a scale from vivid to weak. The presence of brown and gray dictate the color purity.
Tone describes the richness and depth of color from light to very dark.
Let’s use the terms above to describe a fictional blue sapphire. For a particularly rich stone, we could say: “The sapphire has a blue hue with vivid saturation and very dark tone.” Or, let’s say the gem was greenish, light and opaque, we could describe it as having a “slight green hue with weak saturation and a very light tone.”
Understanding sapphire hue, saturation, and tone will help us as we examine each of the sapphire colors.
Are you wondering, what is the color of sapphire? We mentioned earlier that blue is the true color of sapphire, but beyond blue, the gem spans a vast color wheel. In this section, we’ll explore all of the sapphire colors.
Some sapphire stones are treated to enhance the color, saturation and clarity. Another influential factor on sapphire color is each stone’s origin. For instance, sapphires from Sri Lanka are bright and light, whereas Nigerian and Australian sapphire gemstones tend to be darker.
Also, trace elements like iron, titanium, chromium, copper, and magnesium can flush a sapphire with brilliant shades of pink, blue, yellow, pink, orange, green, and more.
When we broadly talk about sapphires, we’re referring to blue sapphires. Sapphire blue is a term used to describe the gemstone and its color. Considering tone and saturation, the highest valued blue sapphires have a violet and velvety blue hue. The depth of these sapphires ranges from medium saturation to deep, dark blue, offering exceptional versatility for jewelry designs.
However, a blue sapphire’s darkness shouldn’t overpower its clarity. In other words, dark sapphires that retain intensity and brightness will fetch the highest price-per-carat.
Conversely, blue sapphires with a grayish tint or are too light or dark are less valuable stones. That said, this doesn’t mean they’re tossed aside; they just fall in a lower price point.
Yellow sapphires primarily come from Sri Lanka, and range from bright to deeply saturated. These warm-hued gems have undertones ranging from orange to green.
Thanks to their bright, jovial coloring, yellow sapphires pop off the finger, making them a desirable engagement ring choice. Yellow sapphires often have feather-like inclusions that are best concealed with a medium tone.
Pink sapphires are intensely saturated with a bright and attractive color ranging from baby pink to vivid fuschia. The color exudes modern femininity, making them aesthetic engagement ring stones beloved by celebrities like Blake Lively and Lady Gaga.
This blushing gem’s cut plays a large role in its ability to exude optimal light and color. A skilled lapidary will cut away the inclusions to allow the most light to enter and reflect through the stone.
Sunset-hued padparadscha sapphires are extremely rare and radiant, varying from light pink to pinkish-orange. The word padparadscha comes from the Sanskrit term, tropical lotus flower. Perhaps the only thing rivaling this stunning imagery is the gem itself.
Padparadscha sapphires aren’t only rare to sapphires, but to gemstones in general. Do you know what that means? They fall into a much higher price point. It’s worth the investment, considering the vivid and intensely saturated blend of pink and orange, offering the perfect union of sparkle and romance.
Also known as violet sapphire, or plum sapphire, these gems range from bluish purple to pink-purple, but predominantly have pink undertones. Considered rare amongst sapphires, naturally purple sapphires require no heat treatment or enhancements to bring out their lustrous color.
Golden hued sapphires are bright and full of warmth, ranging from yellow-orange to burnt orange. These carnelian-like gems exhibit a strong, consistent orange color that appears almost reddish.
We can thank the union of trace elements for the stone’s color: Chromium provides red and iron creates yellow, resulting in a fiery, amber-hued orange sapphire.
Green sapphires are popular, but not as valuable as other varieties because of their dim saturation. Unlike emeralds, green sapphires range from mint to olive to forest green.
Green sapphires may have yellow undertones, resulting in an olive coloring, or blue undertones, leaning more toward the mint or aqua color spectrum.
A once rare stone, green sapphires have risen in popularity in recent years. The green sapphire is called the “stone of tranquility,” for its calm, serene coloring — a well-deserved moniker for such a peaceful stone.
In its most natural form, corundum is colorless, resulting in white sapphire gemstones. White sapphires have a high value as they are pure corundum, a hard crystalline mineral giving them clarity and purity. These colorless gems are a popular alternative to diamonds, thanks to their hardness and budget-friendly price points.
However, some white sapphires exhibit faint undertones like brown, blue and yellow, which lowers the value. Jewelers popularly use white sapphires to accentuate other stones in jewelry pieces, or as a center stone for engagement rings.
If you thought diamonds were a girl’s best friend, you might want to take a closer look at white sapphires!
Chameleon sapphires are gemstones that exhibit pleochroism, an effect where the gem changes colors under different lighting. For instance, in broad daylight, chameleon sapphires vary from blue to lavender or violet. However, under lamplight or incandescent light, the same stone appears to have purple or red tones.
Neat trick, right?
Chameleon sapphires are popular and graded by the depth of color shift across lighting conditions. For instance, whether the gemstone’s change is strong, medium, or weak dictates its value.
Star Sapphires naturally have silk-like, fibrous inclusions that reflect light in the shape of a star. The star can have between six to twelve rays that flash a milky glimmer across the face of the stone.
This feature is called Asterism and evokes a striking contrast between the gem’s body tone and milky star shape. However, sometimes the star is too light, making it less visible and ultimately, less valuable.
While this natural phenomenon is unique, Star Sapphires are relatively common. Just keep in mind that those exhibiting a clear star against a strong base color will have the highest value.
We’ve covered every sapphire color, but what about red sapphires — do they exist? Rubies and sapphires come from the same corundum mineral class. However, the presence of chromium transforms the gemstone into a vivid red.
It’s important to understand that if a sapphire is predominantly red, it’s considered a ruby gemstone. If the red hue is faint and leaning toward pink, it’s a pink sapphire. Fortunately, distinguishing the two is easy: ruby red is an unmistakable color.
Gemstone inclusions are generally regarded as “flaws.” However, inclusions can also add value when they create a rare or unique feature. Remember the Star Sapphire? The light-ray optical effect is called asterism.
Asterism occurs from tiny mineral fibers inside the gem that form dense inclusions, creating a starburst effect. However, not all inclusions result in a neat geometric shape.
Needle-like rutile inclusions called silk are the most common, and they dim the stone’s transparency. However, when they form in parallel groupings, they become Star Sapphires.
Quite a stunning phenomenon, right?
When sapphires form, they often consume light to opaque trace minerals like zircon, spinel, mica, hematite, and calcite. These inclusions are virtually invisible in white sapphires. Which means, the darker the sapphire, the more visible the inclusions (if present), and the more opaque the gemstone.
Another variation are liquid inclusions: carbon dioxide fluids trapped inside a sapphire mined from metamorphic rock. In fact, you can trace a sapphire’s origin by examining its particular inclusions.
Sri Lanka/Ceylon: Halo-like inclusions from trace elements of mica, pyrite, and zircon.
Kashmir, India: Tourmaline crystals are present within the structure
Burma: Long rutile needles, apatite crystals, convoluted feathers, silk, and sometimes hexagonal color zoning.
Sapphires form over millions of years in metamorphic and igneous rocks. Sapphires begin as corundum, but when they encounter nearby minerals, they acquire a new color.
Sapphire deposits exist worldwide, with primary mines located in:
Myanmar (formerly Burma)
How do we value a sapphire? We’ve gone into great detail about color, which is the single-most vital detail influencing a sapphire’s value. Sapphires exhibiting vivid saturation and the true blue hue are the most desired, and thus, the most valuable. Next to blue, padparadscha sapphires are the most expensive, thanks to that intoxicating sunset hue.
But there’s more to sapphire value than color.
Like diamonds, we grade sapphires according to the 4Cs: cut, color, clarity, and carat.
For color, the most intense and vivid gem’s are the most valued. If a sapphire’s tone is too dark, it’s not going to fare well on the value scale. When you’re researching sapphires, take enhancements into consideration. While most treatments are common, you still want to know the details of the gem’s history and origins to pay a fair price.
Nearly all sapphire gemstones receive treatment to enhance their natural color and clarity. The most popular enhancement is heat treatment, but specific stones benefit from varying treatment methods.
Heat treatment: Rutile (silk) inclusions melt at a lower temperature than corundum. Applying heat for a controlled period helps to absorb the rutile inclusions into the crystal structure. In turn, this improves the sapphire’s clarity and color.
Diffusion: Applying a thin color layer on the stone’s exterior greatly enhances both color and asterism. Diffusion is mostly used for blue sapphires and is undetectable unless submerged in refraction liquid.
Irradiation: Treating light colored sapphires with irradiation enhances them with warm tones like yellow and orange, but the process (while untraceable) is rare.
Synthetic sapphires were invented in the early 1900s by a process called flame fusion. In addition to flame fusion, gemologists can create synthetic sapphires using flux, Czochralskior, or hydrothermal solution.
These processes effectively grow a sapphire in a lab by recreating the natural environment in which sapphires grow. Using extremely high heat and intense pressure, a sapphire grows from a solution.
Alternatively, the gemologist can melt aluminum oxide powder composed primarily of corundum to form a sapphire droplet.
While synthetic sapphires aren’t as valuable as real sapphires, they’re prevalent in the gem trade.
Read more about Synthetic gemstones here.
There’s a good reason why sapphires are so popular: there’s a color for everyone out there! Not to mention the gem’s durable composition and wide availability.
Are you looking to buy high-quality sapphires online? Whether you’re in the market for a true blue sapphire, rare padparadscha, white sapphire, or fancy colored variation, Gem Rock Auctions is the source for all of your sapphire dreams.
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