Onyx

Lore & Background

Onyx comes through Latin from the Ancient Greek ὄνυξ (onyx), meaning 'claw' or 'fingernail', as pink and white bands can resemble a fingernail. It is cryptocrystalline, consisting of fine intergrowths of quartz and moganite, with parallel bands unlike the more chaotic banding in agates. Sardonyx is a variant with sard (shades of red) bands instead of black. Black onyx is the most famous variety but is not as common as colored onyx; most "black onyx" on the market is artificially colored. Artificial treatments have been used since ancient times to produce black, red, and yellow colors. The first-century naturalist Pliny the Elder described techniques of soaking or boiling chalcedony in sugar solutions, then treating with sulfuric or hydrochloric acid to carbonize absorbed sugars. These methods are still used, along with other dyeing treatments, heating, and nitric acid to lighten or eliminate undesirable colors. The name "onyx" has also been applied to softer banded carbonate materials from Mexico, India, and elsewhere, which are more readily available and often carved and sold as onyx. Onyx has a long history of use for hardstone carving and jewelry, usually cut as cabochons or beads, and for intaglio and cameo engraved gems where bands create contrast. It was used in Egypt as early as the Second Dynasty for bowls and pottery. Sardonyx appears in Minoan Crete art from Knossos. Brazilian green onyx was used as plinths for art deco sculptures in the 1920s and 1930s, notably by German sculptor Ferdinand Preiss.

Reader's Guide

Onyx is significant as a gemstone and decorative material with a continuous history of use from ancient Egypt and Minoan Crete through the 20th century. Its parallel banding allows for cameo and intaglio carving where contrasting layers create images. The stone is mentioned in the Bible and was known to ancient Greeks and Romans; Pliny the Elder described both natural and artificially treated varieties. Culturally, ancient Romans carried sardonyx amulets engraved with Mars for courage in battle, Renaissance Europeans believed it bestowed eloquence, Persian tradition held it helped with epilepsy, and English midwives used it to ease childbirth. The term "onyx" is often misapplied to softer carbonate materials and other banded stones, and most commercial "black onyx" is artificially colored. Its legacy includes architectural use, such as the shimmering wall in Villa Tugendhat, and its role in art deco sculpture bases.

Did You Know?

• The name 'onyx' comes from the Ancient Greek word for 'claw' or 'fingernail' because pink and white bands can resemble a fingernail.
• Most 'black onyx' sold today is artificially colored using sugar and acid treatments described by Pliny the Elder in the first century.
• Sardonyx was traditionally used by English midwives to ease childbirth by laying it between the mother's breasts.
• Slabs of onyx from the Atlas Mountains were used by Mies van der Rohe in Villa Tugendhat to create a semi-translucent interior wall.

Common Misconceptions (Editorial)

One common misconception is that "black onyx" is naturally the most common variety; in fact, most black onyx on the market is artificially colored, and colored onyx is more common than black. Another is that any banded, dark material sold as "onyx" (such as "Mexican onyx" or "cave onyx") is the same mineral — but properly, onyx is a variety of agate (chalcedony), while these other materials are softer carbonates, alabaster, or obsidian.

Why It Matters (Editorial)

Onyx matters because it bridges natural history and human artistry, from ancient Egyptian bowls to modernist architectural panels. Its enduring appeal lies in how a simple banded stone has been transformed by culture — through ancient dyeing techniques, cameo carving, and even midwifery lore — into a material that continues to symbolize elegance and permanence.