Kohl and galena: the chemistry of 5,000 years of eye paint

In 2010, Christian Amatore and a team at the École Normale Supérieure in Paris published a paper in Analytical Chemistry that did something archaeologists had been arguing about for decades: it analysed the residue inside cosmetic vessels from the Louvre’s Egyptian collection and confirmed what the recipes scratched onto papyrus had hinted at. The black powder ancient Egyptians used to line their eyes was not simply ground galena. It was a deliberately compounded mixture of four lead-based minerals, two of them synthesised in a process that took weeks of patient wet chemistry. The Egyptians, in other words, were making cosmetics by what we would now call a manufacturing process, before they invented the wheel for transport.

That fact reshapes how the cat eye should be understood. It is older than the alphabet, older than the chariot, older than the Greek city-state. By the time Cleopatra was born in 69 BCE, Egyptian women had been refining the same eyeliner formula for at least 4,000 years.

What was actually in the jar

The black-grey paste that filled small alabaster pots in the tombs of Tutankhamun’s contemporaries was made of four ingredients, identified by Amatore’s team and confirmed in subsequent analyses summarised by The Archaeologist’s chemical-analysis review.

Galena, or lead sulfide (PbS), gave the deep grey-black colour. The Egyptians sourced it from the Eastern Desert hills near the Red Sea, then ground it to powder using a stone mortar. Stibnite, or antimony sulfide (Sb2S3), gave a slightly bluer black; it was rarer, imported from Persia, and shows up more in late-period kohl than early-dynastic kohl.

The two surprises were the white compounds. Laurionite (PbCl(OH)) and phosgenite (Pb2Cl2CO3) are not naturally common minerals in Egypt. They are synthetic, made by reacting lead oxide with rock salt and natron in shallow pans of Nile water, then evaporating the slurry over weeks. The Egyptian Museum’s Cairo holdings include lead-salt grinding stones with white residue still on them. Why bother making them? Because mixed into galena, the white salts loosened the paste, gave it a softer texture, and (the 2010 study argued) released a low concentration of free lead ions on contact with the lacrimal fluid of the eye.

The released lead ions did something specific. Christian Amatore’s team showed, in cell-culture experiments published alongside the chemistry paper, that low doses of lead salts trigger keratinocytes to release nitric oxide. Nitric oxide is part of the innate immune cascade. It signals macrophages, which migrate toward the eyelid, which respond to the ever-present bacteria that live around the lacrimal duct. Discover Magazine’s coverage of the study summarised the implication bluntly: Egyptian kohl was an antimicrobial eye-defence preparation that happened to also be cosmetic.

What the Egyptians said it did

Reading the surviving medical papyri (the Ebers Papyrus, dated roughly 1550 BCE, and the Edwin Smith Papyrus, slightly earlier), the claim was that kohl prevented blindness. Modern eyes read that as folk superstition. But the dominant cause of childhood blindness in Egypt was, until very recently, trachoma, a bacterial infection of the eyelid that scars the cornea over years. A daily application of an antimicrobial paste, applied with a stick to the inner waterline, would do exactly what the papyri said it did: keep the bacteria down, keep the eyes clear.

The Egypt Museum’s catalogue of cosmetic vessels notes that kohl was applied to children from the first month of life. It was not vanity. It was preventive medicine that doubled as social signal.

How it spread

Sumerian women lined their eyes with stibnite around 3500 BCE; the recipes shifted along Levantine trade routes to Persia, then to Arabia, where it became known as kuhl al-ithmid (the antimony kohl). Greek women under Roman rule adopted it as mesdeme; Pliny the Elder describes the import trade in his Natural History, complaining about the prices.

The paste survived the fall of every empire that used it. South Asian surma, sold in tiny brass tubes in Karachi or Lahore today, is the same mineral chemistry: ground stibnite or galena, often with cooling agents like camphor added for the modern user. Egyptian khol mehnat, in the alabaster-and-brass tube design that has not changed in two centuries, is sold at Khan el-Khalili to tourists who do not realise they are buying a Bronze Age formula.

That continuity is rare. There is no other personal-care product on a Western bathroom shelf that traces, line by line, back to a recipe written on papyrus.

The complication

The cosmetic that the Egyptians used had measurable lead in it, and modern toxicology takes lead exposure seriously. The 2010 study argued that the dose from ritual eyeliner application was small enough that the antimicrobial benefit outweighed the risk; that is a defensible position for an adult applying a thin line once a day, and a less defensible one for daily lifelong exposure starting in infancy. Lead accumulates. The skeletal remains in some New Kingdom burials show raised lead levels.

Modern Western kohls, by regulation, contain no lead. The FDA bans lead acetate from US cosmetics. Anything sold in Sephora as “kohl” is a black wax pencil with carbon black or iron oxide as the colourant; it has nothing to do with the ancient formula except the name. If you want the actual mineral chemistry, you have to buy it abroad, and most ophthalmologists will tell you not to.

The interesting thing, for a journal that cares about the why, is that the modern formulations have lost the antimicrobial property along with the lead. A carbon-black eyeliner does nothing for trachoma. The trade for safety was a real trade.

Wearing it now

The look survives even where the chemistry doesn’t. The ancient Egyptian tutorial walks through the long extended tail and the doubled lower lid line that show up on every preserved Eighteenth Dynasty portrait. The contemporary descendant, an Arabian Bollywood liner, runs the line further out and adds a smoke at the outer corner; it shares the geometry without the lead.

The Arabian glam tutorial takes the kohl-built eye into a modern editorial register, with a cut crease and a heavy lower lash line that reads as direct lineage. None of these looks invented anything. They reinterpret a 5,000-year-old shape.

The point of telling that history is not nostalgia. It is to notice that beauty work, the daily ritual of putting paint on a face, has been continuous human behaviour for longer than written language. The lipstick is younger than the eye paint. The mirror is younger than the eye paint. What we do at the bathroom counter every morning is older than civilisation, and the women who first did it were, by the standards of their time, doing applied chemistry.