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Onyx Gemstone – Your FAQs Answered

Black onyx faqs guide

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Onyx is a popular gemstone, used throughout history for various purposes including artwork and jewelry making, especially during the Victorian Era. In the past, onyx was an expensive and highly valuable gemstone but today it’s one of the more affordable stones. With its unique, attractive color and sleek look, onyx is a great addition to any jewelry or gemstone collection.

If you’re considering buying a piece of onyx, take a look at these 12 frequently asked questions, covering everything you need to know about it.  

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What is onyx?

Onyx is a gemstone that’s formed from layers of chalcedony, a silicate mineral made of calcite. It’s similar to agate, the only difference between the two being that agate contains curved bands while onyx has parallel layers. In ancient times, onyx has been used in jewelry as well as in gem therapy and was also considered to be a protective stone.

Onyx gemstone box

A beautiful onyx gemstone box for jewelry by Erebore. See it here.

Onyx is a historically significant stone which has been used since the ancient times for jewelry and  hardstone carvings. The ancient Egyptians used it to make pottery items while the Austrians used it to create pin dishes and trays. Today, the mysterious charm of onyx, its affordability and the increasing demand of black jewelry has made it a highly sought after and popular gemstone in the jewelry world.  

There are several varieties of onyx, classified according to their different color bands. These types include the following:

  • Sardonyx – This gemstone has flat bands and a brown base with reddish color bands. It’s one of the most common and affordable types of onyx.
  • Niccolo Onyx – This type of onyx has an extremely thin upper layer through which the dark color of the black base can be seen. It mostly appears as blue or grey.
  • Cornelian Onyx – Unlike niccolo and sardonyx, cornelian onyx has lighter colored bands on a red base. The alternating white and red bands give the stone a unique and attractive look.
  • Black Onyx – Some varieties of onyx have a single color without any color banding, black onyx being the most famous type. Black onyx is rarely found in nature which is why most of the black onyx found on the market today is made of grey chalcedony that’s been treated and turned into black onyx.

What color is onyx?

Green onyx earrings

A pair of green onyx earrings by Amy Fine Design. Check price here.

Although most people think that onyx is always black, its available in a wide variety of colors ranging from white to black. Some of the most common colors and shades include green, blue, red, gold, brown or gray. Lighter colored onyx stones are slightly translucent and every color comes with its own unique variations.

How is onyx formed?

Onyx is an interesting and unique gemstone, rarely formed in cavities in lava. These cavities are filled with gas and when silica gets deposited in them, it creates the distinctive stripes or bands that are typically present in the stones. The banding occurs in either black and white or brown and are straight, unlike the bands in quartz (also known as agate). This is why agate is commonly mistaken for onyx.

Onyx is also formed naturally in caves when water drips from the ends of stalactites and stalagmites and evaporates, leaving traces of calcium carbonate and minerals behind.

Are onyx stones treated or enhanced?

Since natural onyx is very rare, the production of artificial stones has increased greatly over the years, which is why it’s now available to everyone. Most artificial onyx stones are produced from plain agates or chalcedony using certain techniques and treatments to make them look exactly like real onyx.

One particular treatment involves boiling or soaking chalcedony in a sugary solution. The stone, which is porous enough, absorbs the sugars into its top layers and is then treated with hydrochloric or sulfuric acid. This process converts these absorbed sugars into carbon or charcoal (known as carbonizing), giving the stone the desired color.

These dyeing techniques along with many others are still used today and are responsible for the creation of most of the black onyx on the market today. Some stones are heated and treated with nitric acid to remove any undesirable colors or to lighten their existing colors considerably.

How should I take care of my onyx gemstone?

Onyx is a fairly hard stone with a ranking of 7 on the Mohs scale, which is equal to the hardness of quartz. Although the composition of this gemstone is tough, its prone to damage and a hard blow or bump can crack or chip the stone. This means that you’ll need to take special care of your onyx piece, keeping it away from other gemstones that are harder since they can scratch and damage it.

Store your onyx piece safely in a jewelry box or wrapped in a cotton cloth. It’s also important to keep it away from harsh chemicals, perfumes and cosmetics since these can damage it, making it lose its brilliance and giving it a dull look. Take the stone off before you go swimming since onyx absorbs water and the chlorine in the water can damage it.

Where can you find onyx?

Onyx is found in several parts of the world including Argentina, Australia, Canada, Brazil, China, German, India, the UK and many of the U.S. states. Natural, black onyx , which is the most famous type, very rarely occurs in nature and most of the solid black stones found on the market today are actually agate that’s been artificially colored.

What does onyx symbolize?

In ancient Persia and India, onyx was regarded as a protective stone, that kept its wearer from evil. It’s beautiful design and the contrast between its black and white layers were also symbolic of the love shared between two people. Some believed that this unique stone was also a protector of close, harmonious relationships and it has been considered so ever since.

Black onyx, however, has often been connected to bad luck throughout history. In Arabia, it was called ‘el jaza’ meaning ‘sadness’. In ancient China, onyx was mined by slaves and servants and people were afraid to touch the gemstone, believing that it would give them bad dreams, bring about misfortune and cause them to lose their energy.

Even today, many believe that onyx brings bad luck and only those born in the month of December can wear it since it’s the mystical birthstone for December.

How can you tell if onyx is real?

When shopping for onyx gemstones or jewelry, it’s important to keep in mind that many of the black stones sold as onyx are made of softer material. Therefore, it can be very easy to wind up with a fake one. 

The easiest way to determine whether or not the gemstone you’re buying is a genuine one is to check its surface carefully. High quality onyx stones have a slightly transparent look and a polished, reflective surface. There shouldn’t be any scratches or cracks and the surface should be completely smooth and clean. View it under different types of light since poor light can make it difficult to see any scratches or imperfections in the stone.

Does onyx have healing powers?

Onyx is a popular stone used for gemstone therapy and is believed to have several healing properties. Black onyx is said to promote steadfastness, stamina and vigor and treats blood, bone marrow and bone disorders. Some of the most common healing properties of onyx include: enhancing your focus, encouraging clear thinking and sensibility, enhancing protection, shielding you from evil and negative energies. Onyx is also believed to relieve (or even cure) problems in the teeth and feet.

Disclaimer: Wedding KnowHow does not guarantee or validate any of the claims related to the metaphysical and alternative healing powers of this or any other gemstone. This information should in no way be used as a substitute for medical advice.

How should I clean my onyx gemstone?

Onyx ring

Onyx ring by Delarah. Check price here.

Taking care of your onyx stone or jewelry is important if you want it to last a lifetime. Remember, onyx is a porous stone which means that it easily absorbs liquids, so never wash it under running water or soak it. Instead, use a dry, soft cloth or brush to wipe off any dirt on the stone.

If the piece just doesn’t feel clean enough, moisten a soft cloth with a little water and wipe it carefully. Once you’re done, wipe it gently with a paper towel or another soft cloth and store it away in a safe place. Never use any cleaning liquid (not even soap) on your stone since it can cause discoloration.

Is onyx valuable?

Although onyx was a valuable gemstone in the past, it’s now highly affordable. It can be found in a wide range of prices to choose from, according to your budget. This is why onyx is a popular choice for statement pieces and costume jewelry.

Vintage onyx ring

Mid-century vintage onyx ring by Maejean Vintage. See it here.

While onyx gemstones themselves aren’t costly, the overall design of a piece containing it can be of value. Vintage and antique jewelry items containing onyx are usually valuable, especially when the gemstones are set in precious metals such as white, yellow or rose gold and platinum, to name a few.

Black onyx is the most valuable variety of onyx available, its price ranging from $1 – $500 per carat. The price varies with the type of setting and the metal used. For example, an onyx stone in a silver setting will cost far less than one in a setting of white or yellow gold.

Where can I buy onyx jewelry or stones?

If you’re looking to buy onyx gemstones or jewelry and you can’t seem to find the ideal piece at your local jewelers, we recommend searching online. However, make sure that the retailer is trustworthy and check for good after sales policies. Also check the customer review to gauge the quality of the product.

  • Blue Nile, the largest and best known online diamond retailer, has a small but exclusive range of onyx pieces at very reasonable prices. All pieces from Blue Nile are of excellent quality and there’s always something for everyone.
  • Etsy has a vast selection of onyx jewelry and stones ranging from a few dollars to thousands of dollars. It’s one of the best places to search if you’re looking for something that’s truly one-of-a-kind.

Wrapping Up

While onyx is a fairly cost-effective gemstone, it has a stunning, expensive look that makes it well worth its price. It’s an excellent choice if you’re looking for a gorgeous, classy and mysterious gemstone to add to your collection. While onyx is possibly the most popular black gemstone, there are other black gemstones used in jewelry. Check out our list here.