by Yuman Hussain
Most of the black onyx which is produced commercially is heated and permanently dyed to enhance the depth of the black color making it exotic.
Black Onyx- Facts and Buying guide
An anniversary gemstone for the 10th year of marriage black onyx looks elegant as a piece of jewelry. Onyx is one of the banded varieties of Chalcedony or Agate. It is known as ‘nail of a finger or claw’ in Greek mythology. The attributes ranges from translucent to opaque in some stones and strongly white or black banded. Coming in varieties of colors including brown, white, grey and black the one which looks most stunning is the black Onyx. It is basically Agate which is dyed to get the black color. Used traditionally for carving cameos, you will often find it as shiny background for any jewelry due to its fine texture and smoothness. Sardonyx is onyx with white bands or ribbons on black or brown background and is different from black colored onyx.
Black onyx is most commonly available stone world over. This stone is mined in many countries including Brazil, Mexico, England, Pakistan, Uruguay, India and California. A type of microcrystalline Silicon dioxide it is used extensively for carving and no doubt in great demand with lapidary artists due to its hardness which is 7 on Mohs scale. The specific gravity ranges from 2.65 to 2.66.The Refractive index or R.I is 1.543-1.552 to 1.545- 1.554.The optical sign is positive with uni axial optical character.
Right from the antiquity Onyx as a stone is dyed to improve the color and texture. Dyeing is a process to alter the color of a gem by dipping it in a solution to allow the dye penetrates through fractures present in the stone. Black onyx was first made some 4000 years back in Harappan civilization. In fact one can make black onyx by keeping banded agate into the solution of honey and sugar water over low heat for couple of days. The porous bands will absorb the liquid and when heated the sugar will caramelize producing deep brown color. If these stones are further put into Sulfuric acid the sugar will carbonize producing black color onyx. This method is in use since ages and said to produce permanent result. Most of the black onyx which is produced commercially is heated and permanently dyed to enhance the depth of the black color making it exotic. The natural onyx is extremely rare to be found. The dye used in the process is stable and one should be careful while cleaning to avoid removing or dulling this stone. Irradiation is another process which is used for producing different colors.
Black Onyx chip or get scratches easily if not handled carefully though it is easy to clean the stone with any commercial jewelry polish. After polish the piece should be washed with hot water and dried with soft cloth. A drop of Olive oil can produce beautiful shine to the stone. A plain water rinse can also clean the dirt but never soak the stone as it can fade the dye. Do not keep two stones together to avoiding touching. It is best to avoid excessive heat, light, heavy chemicals, steam cleaners or any heavy duty cleaning aids to prolong the durability of the stone.
It is widely believed that black onyx can change your erratic habits for good if used with faith. It is considered as one of the powerful protection stones as it absorbs negative energy relieving people of mental stress and promotes emotional well-being. Black onyx is associated with planet Saturn and it said to bring positive vibes for those with a strong Saturn in their birth charts. In Indian traditions it is said to help people forego their past relationships bringing the person in harmony with the present. It is common to find rosaries made of black onyx as it is believed to have medicinal benefits.
Black onyx is an affordable stone and available in various sizes. While buying, check for smooth marble like surface. The stone should not have any scratches or dents. Sometimes black onyx is confused with black jade, black Chalcedony, black diamond, glass or plastic. The black onyx jewelry looks really beautiful when put together with stones like pearls. If you want to look mystical then go for black onyx.