Onyx History & Characteristics

Onyx comes in many shades of color, including the most popular black onyx. Photo ©2019 EraGem Jewelry.   Onyx is a striking variety of microcrystalline quartz which forms in parallel bands. Found all over the world, it has captured the imagination of mankind all the way back to the ancients. Indeed, the Ancient Egyptians, Greeks, Romans, and Minoans used the coal black stone for carving.  

Onyx Characteristics

Onyx belongs to the family referred to as chalcedony, which also includes agates. However, whereas agates form in curved bands, their counterpart forms in parallel bands. Jasper is another member of the chalcedony family. All members of the chalcedony family form in a variety of colors, primarily earth tones. Also, they typically possess a waxy luster that lends them a striking presence. Jasper, carnelian, chrysoprase, and heliotrope all belong to this family of minerals. In the world of gemstones, onyx typically refers to the lustrous, pitch black stone seen in the photo above. However, this variety of chalcedony actually forms in a variety of colors, often banded together in multi-hued layers. Indeed, it can be brown, red, orange, yellow, and even blue and gray. It often occurs with creamy white bands layered in between the solid colors.  

Onyx Formation

Quartz is one of the most abundant silicate minerals on earth. Erosion and weathering serve to create what geologists refer to as cryptocrystalline particles. Ground so fine, these particles remain vague even under high magnification. These Lilliputian mineral particulates come together in a silica gel of sorts, which oozes into the gas bubbles that form within cooling volcanic rock. Over time, this gel solidifies in bands of color, becoming onyx. Given the abundance of quartz silicate, this versatile semi-precious stone occurs on every continent, in nearly every country in the world. Primarily, gemstone quality specimens comes from Turkey, Mexico, and Arizona. (source)  

Used by the Ancients

This semi-precious stone has been used for ages to create works of art and useful pottery. The Romans and Greeks favored it for cameos and intaglios. The Egyptians fashioned bowls out of the stones, as well as pottery and other functional items. In more recent history, black onyx experienced a revival during the Art Deco period. At that time, jewelers used the jet black stone to provide beautiful contrast with green jade, blue sapphires, rubies, emeralds, and white diamonds. It has also been used to create sculptures, platforms, and even interior walls for architectural feats. No matter how onyx appears, whether as ancient artifacts, Art Deco jewels, or more recent retro designs, it is absolutely beautiful. ~Angela Magnotti Andrews