Onyx is silicon dioxide with the chemical formula SiO2. Like agate, it is a special kind of chalcedony, which is itself a cryptocrystalline variety of quartz. The crystal system of onyx is trigonal; its hardness is 7 on the Mohs scale and its density is between 2.65 and 2.66. It has a conchoidal fracture and its luster is vitreous. Onyx is often striped black and white, but also sometimes only black: in jewelry, in this case, it can also be a chalcedony tinted black according to a process accepted because practiced since very remote times. In this case, it is opaque while the natural black onyx is translucent.


Onyx has a texture in parallel zones, generally black and white (ribboned onyx), or brown and white: in this case it is called sardoine or sardonyx. The bands of onyx are generally circular, and if they are not very marked around a dark core, it is said to be "eye". If the bands are polygonal rather than circular, it is said to be "with fortifications". Please note, "onyx marble" and "onyx alabaster" are other stones only called so because of their texture.


Onyx forms at low temperatures in acidic or basic volcanic rocks, in fissures of igneous and metamorphic rocks, in hydrothermal veins, and rarely in sedimentary zones. Sometimes the erosion of these veins has released the onyx which is found in the form of pebbles polished by the water.
The main onyx deposits are found in Rio Grande do Sul in Brazil, in Chihuahua in Mexico, in Colorado and Utah in the United States, as well as in India, Uruguay and Madagascar.


The choice of an onyx piece of jewelry depends above all on personal taste, the color effect you are looking for and the quality of the polishing. The skill of the lapidary in taking advantage of the layout of the white and black areas counts for a lot in the aesthetics of the gem.
Onyx can be cut in briolette, in drop, in pearl, in sphere (for signet rings, cufflinks, pendants…), in egg, or in any shape of animal or decorative object ( candlestick, bookend, vase, cutlery handles…). Of course there is also cameo (relief drawing) or intaglio (intaglio) carving which has been practiced for millennia.


The word “onyx” comes from the Greek, it means “nail”: in antiquity this term initially designated all the chalcedonies, some of which had the color of the nail. Later, the designation was restricted to the darkest chalcedony.
In Rome, onyx was very popular for making cameos and seals, because it had the property of not sticking to wax.
Greek mythology has a legend about onyx: one day when the beautiful Aphrodite was fast asleep by a river, Cupid came to cut her nails with the iron of one of his arrows. The clippings fell on the sand of the bank, and were transformed into onyx stones by the Fates.
As often, in the Middle Ages, traditional beliefs were linked to the appearance and color of things, onyx and its dark shine was linked to evil spells, hatred and anger, in short to everything that could be influenced by the forces of evil...
However, in the Bible, onyx is mentioned when the Lord speaks to Moses and gives him precise instructions down to the smallest detail to have him erect a sanctuary and prepare the vestments and insignia of the priests. It is written: “Then you shall make a breastplate of Judgment…; there will be four rows of stones […] and the fourth row: chrysolite, beryl and onyx. »


Contrary to what we know of medieval beliefs, lithotherapists attribute great and completely positive qualities to onyx. It would be in a way the stone of stability and reinforcement. This stone would be linked to the root chakra, the one that is at the base of the spine and contains the "kundalini", vital energy rolled up there, three and a half times on itself like a snake. Onyx is said to help build self-esteem, confidence and self-control. It would stabilize people with an inconstant character and give strength to face the upheavals of life. Catalyst for a successful meditation, it would help to find what one seeks there, therefore to better see the true nature of things.
Another important quality, onyx would make it possible to purify karma, that is to say to overcome the consequences of acts or traumas dating from past lives.
From a physical point of view, onyx would have protective virtues for the teeth and the mouth, it would facilitate speech if it is too fast or poorly controlled and would fix vocal problems. In addition, it would increase resistance to cold, sharpen the functioning of the five senses and in particular, would act on ear problems (balance, inner ear, tinnitus).


Black onyx is said to be linked to the signs of Leo, Capricorn and Sagittarius, while striped onyx is said to be associated with Virgo, Scorpio and Libra. Its element is fire and its planets, depending on the case, would be Mars, Jupiter and Saturn. Onyx weddings correspond to the 89th wedding anniversary!

The Science of Onyx

In its natural form, onyx is a slightly transparent black stone composed of silicon dioxide, but it can be found in many other colors once dyed for commercial or decorative purposes.
The primary geographical source of onyx is located in South America and India.
It has a trigonal conchoidal crystal system and a Mohs hardness of 6.5-7.

Onyx throughout History

Its name comes from the Greek word onux , which means “fingernail” given its subtle transparency. For the ancient Chinese civilization and many cultures during the Middle Ages, onyx was seen as a bringer of bad luck, awakener of doubts and dreadful dreams and terrifying madness.
But in India, onyx is a symbol of calmness and strong concentration levels, and as a pacifier of the restless loving emotions. Indians believe that onyx contains a trapped demon inside of it and, therefore, it effectively repels against evil spirits and the evil eye.

In Ancient Rome, onyx was an inspiring stone for craftsman that produced some of the most beautiful and luxurious cameos and furniture ornaments the world has ever seen.
Onyx's healing properties

This stone is associated with the strong gravitational force of our planet and it's thought of as a mineral with the power to ground its bearer and help it connect with the energies of the environment, while at the same time it filters out the negativity in order to effectively open a door between the individual and the higher powers.

Onyx is a stone of spokesman and lovers, for it can bring the eloquence needed to move a nation or to make a loved one fall under one's sincere verbal spell of truth.
Because it can align the energy between one's thoughts and one's words, onyx enhances communication skills and can both bring everlasting happiness to a married couple, or help one gather the facts and strength necessary to bring a bad relationship to an end.

Onyx is connected with transformation from one's very soul and like few other minerals it can help those struggling with overcoming negative and destructive habits, allowing internal peace to arise in the most troubled of minds.
Physically, onyx boosts the body's energy levels and lowers the impact of the stress of the day-to-day life.

Onyx care

In order to properly clean an onyx stone, simply rinse it in lukewarm and plain water and rub it lightly with a very soft polishing cloth. One can also put a drop of olive oil directly on the stone and rub it to recover the onyx's natural shininess.