The gemstone sapphire comes in virtually every hue, including the lesser-known black sapphire. Do black sapphires exist in nature? Yep! These stones form naturally, and black is one of the most common sapphire colors.
However, many jewelers consider black sapphires lower-quality options than other sapphires. The one exception for most jewelers is black star sapphires, which are prized more highly for their bright, celestial optical effect.
Of course, normal black sapphires are still beautiful, unique, and budget-friendly gems. In this guide, we’ll break down black sapphire properties, quality, benefits, and more!
Even non-jewelry industries have been inspired by black sapphires.
One example is the L'Oreal Paris hair dye color called “Black Sapphire.” Another instance is a pure black metallic BMW car color also called “Black Sapphire.”
Black sapphire can also substitute for black onyx as a mystical December birthstone and Leo zodiac stone.
Speaking of, is black sapphire the same as onyx? No, but they do have some similarities — along with key differences.
Pictured above: Onyx
Black sapphire looks similar to black onyx, but there are key differences:
Hardness: Black sapphire is harder, ranking at 9 on the Mohs scale while black onyx ranks at 7.
Origin of Color & Rarity: Naturally black sapphires are pretty abundant, but solid-colored black onyx stones are so rare, the majority available have been dyed
Luckily, both black onyx and black sapphire are great ring stones, though black sapphires are slightly better.
This may be why some newlyweds opt for black sapphire engagement rings as non-diamond alternatives.
Black sapphire is a corundum mineral, which encompasses rubies and sapphires. These aluminum oxide minerals are colored by various impurities, like the iron and titanium impurities in black sapphire.
How can you tell if black sapphire is real? There are some properties to help.
First is magnetism. Among sapphires, black sapphires are the only ones that are strongly magnetic.
Second is hardness, which can help differentiate black sapphires from imitations. Sapphires are quite hard, only softer than diamonds and moissanites, so they shouldn’t scratch easily. Almost any imitation will be softer, often around a 7 Mohs ranking.
Here are the remaining black sapphire mineral data:
Mohs hardness: 9
Color: Black, gray; Very dark blue, green, or purple
Crystal structure: Hexagonal (trigonal)
Luster: Sub-metallic to vitreous (glassy)
Transparency: Translucent to opaque
Refractive index: 1.76-1.77
Optical effects: Asterism
Below, we’ll expand on that last property listed: asterism.
Before we get into black star sapphires specifically, let’s go over some fundamentals.
Many sapphires can display an optical phenomenon called asterism. These stones, called “star sapphires” or “asteriated sapphires,” have star-like rays of reflected light. Most have six-rayed stars, though some rare specimens have 12-rayed stars.
The phenomenon comes from dense, parallel inclusions that reflect light differently than the sapphire base.
Sometimes, ilmenite and hematite inclusions criss-cross, creating exceptional 12-rayed black star sapphires.
The black sapphire “star” is typically gold. 12-rayed stars may be white and gold.
Next, we’ll explore the symbolism of black sapphires and their starry versions.
As a black stone, it’s unsurprising that black sapphire is often associated with the mysterious and mystical. Overall, black sapphire symbolizes protection, prestige, and power.
Is black sapphire a lucky stone? That depends on who you ask.
Medieval Europeans believed all black stones were lucky and protective. Similarly, an Italian myth claims that touching black diamonds would bring newlyweds good luck.
In contrast, other cultures view black gems as unlucky, sometimes associating them with “evil” (dangerous) animal eyes (e.g. snakes or spiders).
Asteriated stones, historically called “asteria” or “asterion,” have led to various superstitions over time.
Some Christians believe six-rayed star sapphires are “Stones of Destiny,” that symbolize destiny, hope, and faith. Other religious folks use star sapphires to ward off the “evil eye.”
Some believe gazing into a star sapphire induces a trance-like state. Some say this “trance” brings insight into the future. Others believe the stone must be holding a living spirit. Furthermore, some would seek out star sapphires for use in necromancy.
Pictured above: Black Star of Queensland | Image credit: Chatsam, Creative Commons Attribution-Share Alike 1.0 Generic license
The Black Star of Queensland is an impressive six-rayed black star sapphire found in Queensland, Australia, in 1938. This 733-carat gem is currently the world’s largest black star sapphire. Compared to most star sapphires, the Black Star of Queensland has a larger, brighter star.
After the original roughly 1,133-carat specimen was discovered by a young boy, his family actually used it as a doorstop for years.
In 1947, Armenian jeweler Harry Kazanjian bought the stone from Harry Spencer (the young boy’s father) for $18,000. Kazanjian planned his cut for 2 months, eventually removing 400 carats to properly display the star.
The stone went on various tours, including being displayed at the Smithsonian in the 1960s and adorning Cher in 1971.
Though the Kazanjian family doesn’t own the stone anymore, Harry’s grandson, Doug Kazanjian, wears a black star sapphire ring. He describes it: “It’s almost as if you’re looking into space… It’s like having the universe on your finger.”
Speaking of the metaphysical properties, what is black sapphire good for?
Like all gems, black sapphire can be a healing stone. Being a black gemstone, it inherently offers protective and balancing benefits. It’s also a great root chakra stone, balancing this energy center to keep you stable and grounded.
Physically, black sapphires are said to treat or help with:
Emotionally, black sapphire benefits anyone who feels lost in their thoughts or disconnected from their emotions. The crystal is said to balance your emotions and ground you to the present.
Additionally, black sapphires may help you stay calm amidst stressful circumstances, dispel negativity, and relieve anxiety.
As gemstones, are black sapphires valuable? That depends on their quality.
Black sapphire’s value depends on its color, cut, carat weight, treatments, origin (natural vs. synthetic).
Overall, black star sapphires are more valuable than other black sapphires, though their value depends on similar factors. The only separate factors are the star’s quality — larger, brighter, distinct stars are most valuable.
Black sapphire’s color may actually be very dark blue, green, purple, or gray. Pure black hues are most valuable, in both regular and asteriated stones.
Many black sapphires are faceted, often into fancy shapes to make them more appealing and display their luster better.
Black star sapphires must be cut as cabochons to display their star correctly. The best cabochons have the star oriented at the center of the dome.
Black sapphires are abundant, so finding a large one for an affordable price should be easy. However, black star sapphires are less common, so larger stones (above 5 carats) can be pricier.
Most sapphires are heat-treated to improve their color and clarity. Black sapphire’s abundance means treatments aren’t as common, though they’re also sometimes heat-treated to improve their color.
Treatments are more common on black star sapphires. The Gemological Institute of America (GIA) has recently studied a black star sapphire filled with glass and dopping varnish, along with a lead glass-filled black star sapphire.
Additionally, black sapphires aren’t frequently synthesized. Synthetic black star sapphires are more common.
Corundum stones like black sapphire form inside igneous or metamorphic rocks.
In igneous rocks, the stone crystallizes as the rock cools from magma. Longer cooling times creates larger crystals. The igneous rock must be aluminum-rich and silica-poor.
In metamorphic rocks, the crystals often form when ancient sea beds undergo metamorphism from hot, aluminum-rich waters.
Where are black sapphires found? Australia is known for producing the best, largest, and most black sapphires.
Other significant sources include:
Black star sapphires primarily come from:
With origins covered, let’s talk about prices.
First, are black sapphires worth anything? Many gemologists see black sapphires as low-quality — a.k.a, not worth much. Part of the reason is their abundance and opacity, making black sapphires arguably the most affordable sapphires.
The faceted black sapphire price per carat range (at wholesale) starts at $4 per carat and reaches $290 per carat, with most under $40 per carat.
Black star sapphires range from $13-$30 per carat from 0.5 to 5 carats.
Asteriated raw black sapphire specimens are usually under $1 per carat, only reaching around $4 per carat at wholesale.
Be gentler with fractured stones or black star sapphires by avoiding mechanical cleaning systems. Instead, clean your black sapphire (or star sapphire) with a soft toothbrush, lukewarm water, and mild soap.
The benefit of black sapphire being generally overlooked is that it’s affordable and unique. Plus, black sapphire jewelry goes with any outfit, black tie or casual.
Whether you want a go-to gem for pairing with outfits or a mysterious stone that symbolizes power and strength, black sapphire could be the perfect choice.
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