Even when an ancient perfume bottle survives, its original scent may remain a mystery. But a small rock-crystal vessel found in a Roman tomb in Spain still had its stopper and contained solid material. A study of the residue concluded that it most likely contained a patchouli-derived fragrance and vegetable fat.
Published in 2023, the study did more than identify a possible fragrance ingredient. The researchers also examined the mineral used for the stopper and the substance used to seal it, treating the vessel and its contents as parts of a single archaeological object.
A small vessel inside a funerary urn
The vessel was discovered in 2019 during excavations associated with renovation work on a building in Carmona, southern Spain. Underground was a Roman burial chamber containing the cremated remains of six adults and other objects. One of its glass funerary urns held remnants of cloth, amber beads, and the small vessel.
The amphora-shaped vessel was made of rock crystal, or quartz. The researchers describe containers made from this material as rare luxury objects. The surviving solid contents and intact stopper offered a valuable opportunity to investigate what it had once held.
The study asked three questions: What had the vessel contained? What was the surviving solid material made of? And what was the stopper made of? The researchers combined X-ray diffraction to examine minerals, electron microscopy to study elements and surfaces, spectroscopy to investigate molecular bonds, and gas chromatography–mass spectrometry to separate and identify components.
A dolomite stopper sealed with bitumen
The stopper was examined first, before the contents, because material from it might have become mixed into the residue. X-ray diffraction patterns from its inner face, outer face, and edge matched dolomite, a carbonate mineral containing calcium and magnesium. Raman spectroscopy and elemental analysis supported this identification.
There were also dark brown, almost black deposits on the outside of the stopper and around the mouth of the vessel. These contained carbon-rich material that dolomite alone could not explain. Combining spectroscopic findings with molecular markers such as terpanes and steranes, the researchers identified bitumen as a material used for sealing and waterproofing.
Dolomite was also found in pale particles inside the vessel, probably mixed in after material flaked off the stopper. An important step was therefore to distinguish material from the stopper and seal from the perfume itself, rather than treating every part of the residue as a perfume ingredient.
Residues suggested both fat and fragrance
When organic material was extracted from the light and dark particles inside the vessel, the researchers found compounds associated with bitumen, along with sesquiterpenes found in plant scents and components associated with fats.
To investigate the fat, they used a treatment that converted fatty acids into a form more readily measured, identifying components corresponding to oleic, palmitic, and stearic acids, among others. The presence of plant sterols and other compounds also pointed to a vegetable fat.
They could not, however, identify the specific vegetable oil. Its composition may have changed over time, and there was insufficient evidence to narrow it down to olive oil or another particular oil. What the findings support is a picture of contents combining fragrant plant-derived material with fat.
Comparing patchouli and nard with commercial standards
Compounds of particular interest in identifying the fragrance included patchouli alcohol, α- and β-patchoulene, seychellene, α-guaiene, and α-bulnesene. Together, they resembled the composition of patchouli oil.
Ancient plant names and descriptions can be ambiguous, and nard was another possible candidate. The researchers therefore analyzed commercially available patchouli and nard oils using the same method and compared them with the archaeological extract. Its overall component profile was closer to patchouli than to nard.
Importantly, the identification did not rest on finding patchouli alcohol alone. The nard oil used for comparison also contained this compound. The match across multiple components, together with the relatively strong patchouli-alcohol signal, made a patchouli-derived fragrance the leading candidate.
The component proportions in modern patchouli oil and the ancient residue were not identical. The plant species, ancient extraction method, and changes during preservation are unknown. The authors themselves state in the paper that the botanical origin is highly likely, rather than established beyond doubt.
The seal may have preserved clues to the fragrance
The authors suggest adsorption onto bitumen as an explanation for the survival of compounds thought to come from the fragrance. In this account, fragrance components inside the vessel were taken up by the sealing material and later remained on the inner walls along with fragments of the stopper and seal.
The tight seal and conditions in the burial chamber may also have contributed to preservation. This was not, however, a preservation experiment that directly measured the original oxygen level or how much adsorption occurred at each stage. It was an inference about preservation processes drawn from chemical traces in archaeological material.
The study also examined just one vessel. It cannot establish a typical Roman perfume formula, the routes by which patchouli was traded, or precise ingredient proportions. Nor did the researchers reassemble the surviving components and test whether they could reproduce the original smell. Its value lies in using molecular evidence to identify a possible fragrance ingredient that the vessel’s shape alone could not reveal.
Summary
The rock-crystal vessel excavated from a Roman tomb in Carmona retained components consistent with a combination of patchouli-derived fragrance and vegetable fat. Comparisons with modern patchouli and nard oils made patchouli a strong candidate on the basis of the overall composition, rather than a single compound.
The stopper was identified as dolomite, and bitumen had been used for sealing. By examining both what gave the contents their scent and how the vessel was closed and preserved, the study used a single small object to explore an ancient use of fragrance.
The paper declares no external research funding and no conflicts of interest. Its acknowledgments nevertheless also mention individual support for author Daniel Cosano through a FEDER-related program.
Reference
Cosano, D., Román, J. M., Lafont, F., & Ruiz Arrebola, J. R. (2023). Archaeometric Identification of a Perfume from Roman Times. Heritage, 6, 4472–4491. Original research article
