Black Onyx Information — Meaning, Uses, History & More! | Gem Rock Auctions

black onyx informationBlack onyx is a type of layered chalcedony gemstone in midnight black with white bands. The onyx stone has been the choice material for jewelry cameos for centuries. Over time, the term "onyx" has evolved to describe any engraved stone material with a solid body tone. Despite the various interpretations, onyx is a natural gemstone in its own class. The most popular variety is black onyx, a traditionally exceptional gemstone for jewelry, carvings, and décor. 

What is the meaning of black onyx? Is black onyx valuable? And what is black onyx used for, anyway?

You’ll find everything there is to know about onyx gemstone information in this handy guide, so come along to learn all about black onyx gemstones!

black onyx gemstone

What is Black Onyx?

Like agate, onyx is a chalcedony mineral composed of microcrystalline quartz. Adding to the intrigue of this mysterious gem are banded layers of milky white. The stark contrast provides the perfect depth for skilled artisans to carve intricate jewelry cameos and intaglios. The stone’s black base offers the perfect backdrop to allow the white upper layer to illuminate figurines, sculptures, and portraits carved by a skilled hand.

And they’ve been around since antiquity. 

Is onyx a precious stone? No, black onyx is a semi-precious gemstone. While black onyx was a prized gem during early civilization,, it has gradually decreased in value and prestige over time. Black onyx is still a popular gemstone, but it doesn’t have the same admiration as diamonds or sapphires. But let’s not disregard this unique gem, as it still has contemporary uses and benefits.

While it’s often confused with agate, a sister gemstone, the two are different gemstones. Black onyxes with banded white are commonly marketed as agate, so onyx as an entity has blurred within the gem market. Additionally, most people are more familiar with sardonyx, a warmer-toned variety that’s also an August birthstone.

It’s important to understand the difference because onyx has distinct parallel lines, whereas agate has swirling, concentric, non-linear lines. However, distinguishing one from the other can only be done with rough specimens where the parallel lines and banding are visible.

Black onyx is a popular choice for beads, jewelry, and carvings, and you can find the stone in bracelets, earrings, rings, and necklaces.

black onyx gemstone beadsOnyx Specifications

What is black onyx made of, exactly? Below are the onyx geological properties and characteristics. 

  • Onyx chemical formula: SiO2 

  • Mineral class: Chalcedony

  • Varieties: Sardonyx, Carnelian Onyx, Black Onyx, Agate Onyx, Nicolo Onyx

  • Crystal structure: Hexagonal, microcrystalline

  • Colors: Black and white (banded), red, brown, yellow, blue, solid black

  • Luster: Waxy 

  • Transparency: Opaque

  • Hardness on Mohs scale: 7

  • Specific Gravity: 2.651

  • Refractive Index: 1.544-1.553

  • Birefringence: Max 0.009

  • Cleavage: None

  • Dispersion: None

  • Fracture: Conchoidal

  • Treatments: Heat treatment and dyeing

Onyx Variations

Black Onyx

Black onyx beads

Most natural onyx exhibits thin bands of color, but sometimes, you’ll come across an entirely solid-black onyx stone. These are highly rare in nature, though, and typically have surrounding colors in the base rock that lapidaries cut away. Because genuine black onyx is elusive, most stones advertised as solid black onyx are chalcedony stones dyed black.


sardonyx chalcedony gemstone cabochon

Most onyx is black and white, but there are additional variations. For instance, you may have heard of onyx by another name: sardonyx. Are the two the same? Not exactly. Sardonyx is chemically similar to onyx, but its colors differ because the onyx mixes with another chalcedony variety called sard. The result is a stone with warm hues of brown, red, and yellow along with color-banding. 

Niccolo Onyx

undefinedImage credit: Sailko | Creative Commons Attribution-Share Alike 3.0 Unported license

Niccolo onyx has a black base with thin, nearly translucent bands that appear light blue or light gray. The body tone is so black it appears almost blue, like a midnight sky, topped with delicate layers of white.

Arabic Onyx

arabic black onyx gemstone carving intaglio

The most common naturally occurring form of onyx, consisting of a black layer with white on top, is called “Arabic onyx.” Some gemologists call this variety “true” onyx.

Onyx Meaning and Folklore

What does onyx symbolize? The original onyx stone meaning comes from the Greek term onux, which means "fingernail" in English. You just know there’s some rich folklore coming to illustrate the ancient black onyx meaning, right? We won’t leave you hanging. 

Legend has it that Eros, the Greek god of love and passion, rebelliously cut the sleeping goddess, Aphrodite’s fingernails, with an arrowhead. What did the gods do with her fingernail clippings? Transform them into onyx, naturally!

For the Ancient Greeks and Romans, onyx became a choice stone for carving cameos. But the stone was also used for intaglios (negative reliefs, like the ancient Gemma Augustea) that highlight onyx’s beautiful bands.

There’s also exciting symbolism behind the black onyx spiritual meaning. In China, black onyx is a protective and grounding stone used for Feng Shui. Crystal healers use the stone to increase stamina and determination.

Let’s dig a little deeper into the stone’s uses.

Onyx Uses and Benefits

Black onyx is an opaque gemstone that looks best when cut and polished. The cabochon style involves smoothing, tumbling, and polishing stones to best showcase their unique features. In black onyx, the cabochon technique brings out the stone’s milky bands and stripes.

Given these characteristics, what is the onyx stone good for? 

black onyx gemstone ring with diamonds

Black Onyx Gemstone and Jewelry Designs

The most popular use for onyx is jewelry, where the contrast of black against light white bands beautifully compliments earrings, rings, and bracelets. More artistically is the use of black onyx for necklace pendants and cameos. 

The material is soft enough for carving intricate designs but durable enough for jewelry use. The ultimate goal with onyx jewelry is to best display the stone’s bands. Whether it’s Sardonyx, Black Onyx, Carnelian Onyx, or Nicolo onyx, the lapidary or artist will always consider how to best showcase the bands.

Because of the neutral coloring, onyx is prevalent in men’s and women’s jewelry. The stark black color creates a striking contrast when set into gold jewelry metal.

During the Victorian and Art Deco eras, onyx evoked drama and emotional statements. For instance, Victorian women commonly wore black onyx when mourning. And during the geometric, bold Art Deco era, black was an integral color to contrast the glitzy aesthetic.

A fine example of exquisite onyx jewelry is the Van Cleef & Arpels “Manhattan Flowers” earrings set, worn by Adele at the 2012 BRITs awards.

When combined with precious gemstones like diamonds and neutral moonstones, onyx immediately elevates to regal-status.

But without fancy gems in tow, onyx alone is an affordable, diverse gemstone.

black onyx gemstone healing crystal pendant

Black Onyx Metaphysical Properties & Healing

People have used black onyx in natural healing for centuries, thanks to its perceived powers of protection. What are the healing properties of black onyx?

The now mainstream practice of crystal healing uses onyx to ward off negative energies and offer anxiety relief. Like most healing crystals, onyx has physical and metaphysical powers. The stone can help heal wounds, minimize childbirth pains, and improve hair, teeth, nail, and skin health.

Black Onyx Zodiac Stone

Onyx is the August birthstone and zodiac stone for Leo (July 23-Aug 23). Despite the stone’s dark tones, it’s a warm stone boasting creativity and generosity. Wearing an onyx zodiac stone can open the mind, but be wary: there are adverse side effects of dominance, interference, and intolerance.

Onyx Color

The most popular onyx color is black onyx — a white layer above a black base or black stone with milky white bands. Other colored onyxes typically go by different names, as outlined above with Sardonyx, Carnelian onyx, and Nicolo onyx.

What is dyed onyx? Most onyx receives heat treatments and dyes, which is standard practice for many gemstones. Enhancements are applied to bring out the thin layers of color in an onyx stone. Since chalcedony is a porous material, it accepts the dye well and without damage. 

Many black onyxes were once gray chalcedony slabs dyed to turn them solid black. The process involves dipping chalcedony in a solution of sugar and applying heat with sulfuric acid. Keep in mind that unless an item specifies it’s “untreated,” most black onyx has received enhancements.

reddish black onyx gemstone cabochon

Onyx Origins

Where is onyx found? Globally! Onyx forms in silica deposits and gas cavities that grow chalcedony bands in alternating colors. The most prominent black onyx sources are:

  • Brazil

  • Canada

  • Uruguay

  • Madagascar

  • Czech Republic

  • Germany

  • Indonesia

  • Pakistan

  • Australia

  • Argentina

  • France

  • China

  • Germany

  • India

  • Russia

  • Yemen

  • United Kingdom

  • Scotland

  • United States

False Names 

The four onyx types we listed above are universally recognized. However, there are common misnomers you’ll come across. Remember the following names are not onyx, even if advertised as such:

  • Limestone Onyx, Onyx Marble, and Mexican Onyx: These are banded calcite stones from limestone caves. Calcite is a mineral class different from chalcedony quartz, the actual species of onyx. Thus, none of these stones are real onyx.

  • Green Onyx: These are typically chalcedony stones dyed a deep green.

  • Onyx Opal: These contain opal layers, but opal is not onyx in composition, so onyx opal is strictly opal.

  • Rhodochrosite Onyx: A banded rhodochrosite stone variety that is commonly called onyx because of its bands.

Synthetic Onyx

Onyx simulants aren’t a new concept. Pliny the Elder (an ancient naturalist) described synthetic onyx during the Roman reign. Today, making synthetic onyx requires a mixture of chalcedony and agate. Unlike other synthetic gemstones made from lab-created materials, synthetic onyx is a simulation combining various natural gemstones.

Common materials used to create synthetic onyx include black glass, augite, and black spinel. These gemstones are great candidates for onyx synthetics because they are often wrongfully identified as onyx. 

Fun fact: some of the materials used to make synthetic onyx are more valuable than black onyx. Doesn’t that seem odd? The reason is that plan black spinel is almost considered irrelevant in the gem industry. So, the forgotten gemstone has a better chance of selling as a synthetic onyx.

Pliny the Elder described this practice as turning “one variety (of genuine stones) into false stones of another.” In the case of synthetic onyx, the materials aren’t fake, just another species. 

black onyx gemstone earrings faceted

Black Onyx Price and Value

How much is a black onyx worth? Not surprisingly, the price range is vast, and you can buy black onyx anywhere from a few dollars to a few hundred per carat.

Ultimately, it depends on whether you buy loose black onyx stones or fine jewelry. A black onyx gemstone might only cost around $15-$20. But set that same gemstone into a 14K gold ring, and the price jumps up to several hundred dollars. Add in accent stones like diamonds, and the price climbs up to several thousand dollars.

Onyx alone might not hold a high value, but adding fine jewelry accents elevates onyx into the luxury category. Without the frills, it’s a widely available, affordable gemstone.

Onyx Care and Maintenance

While not the hardest gemstone around, onyx is still durable enough for daily wear. Most onyx stones will resist typical scratching and abrasions. Nevertheless, you’ll want to exercise proper care and maintenance to keep the stone in prime condition. 

Fortunately, caring for black onyx is easy: simply use soapy water and wipe it down with a soft, non-abrasive cloth. Because it’s softer than other gemstones, it’s smart to store your black onyx jewelry separate from harder gems like diamonds and sapphires.

black onyx gemstone beads strand

Looking to Buy Black Onyx?

There you have it! That sums up everything you need to know about black onyx information. Ready to shop?

Whether you’re looking for onyx gemstones or intricate carvings, you’re in the right place for all of your black onyx needs! Not only does black onyx makes a great addition to your jewelry collection, but it’s a moody statement piece and conversation starter. Who can resist?

Shop onyx cabochons, onyx rough specimens, onyx gemstones, and parcels to find your newest piece today!


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