# Jet, oil of

**Oglio di gagate**

**Known today as.** Jet is fossilized wood, a dense variety of lignite; the oil was distilled from it.

Kind: Mineral

## What did Canale use it for?

For anointing (ch. 9).

## What does modern science say?

Coal tar, a comparable distillate, does soothe some skin conditions. Pliny says the fumes of burnt jet kept serpents away and relieved hysterical fits, and that the magi used it in divination.

## Pharmacognosy and toxicology

- **phenols and cresols**: of the pyrolysis distillate
- **polycyclic aromatic hydrocarbons**: 
- **sulfur compounds**: 

**Mechanism.** Jet is a lignite, a fossil wood; distilled, it gives a tar oil like coal tar, antiseptic and keratolytic on the skin by its phenols, and carcinogenic by its aromatics. Rubbed on, it would do what coal tar does for psoriasis; burned, its smoke was the fumigation against the womb’s rising. Whitby jet is the same material carved.

**Dose.** Carcinogenic on long exposure; not for internal use.

**Standing.** Coal tar remains a licensed treatment for psoriasis; oil of jet is obsolete.

## What lore surrounds it?

Jet has been mined from the cliffs at Whitby since about 1500 BC; the Romans in Britain carved it into jewelry, dagger handles, dice, and hairpins that traveled the empire, and the monks of Whitby Abbey later made it into rosaries. Its best-known chapter came after Prince Albert died in 1861: Queen Victoria’s forty years of mourning made Whitby jet the material of respectable mourning jewelry across Britain, a fashion that collapsed almost overnight after her death in 1901.

## What did the older authorities say?

**Pliny.** Describes gagates, “so called from Gages, the name of a town and river in Lycia,” as black, smooth, light, and porous, little different from wood in appearance, brittle, and “emits a disagreeable odour when rubbed”; marks made with it on pottery cannot be effaced; its fumes “keep serpents at a distance, and dispel hysterical affections,” detect a tendency to epilepsy, and “act as a test of virginity”; a decoction in wine for toothache; and the magicians use it in axinomancy.

## Sources

- Lang Antiques, on jet.
- Pliny the Elder, *Natural History* 36.34, trans. J. Bostock & H. T. Riley (1855), Perseus Digital Library.
- IARC (2012). *Monographs*, vol. 100F: coal-tar pitch and occupational exposures.
- Roelofzen, J. H. J., et al. (2010). “No increased risk of cancer after coal tar treatment in patients with psoriasis or eczema.” *Journal of Investigative Dermatology* 130.

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*Jet, oil of.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-01. The Thinking Press. https://thethinkingpress.org/materia-medica/jet-oil-of

Historical description, not medical advice.