elements
Lead
Pb
- Also known as
- plumbum
- Crystal system
- cubic
- Hardness
- 1.5 on the Mohs scale
- Lustre
- metallic
- Colour
- Dull grey
- Where it forms
- Native lead is very rare; almost all lead comes from galena.
- Chiefly from
- SwedenRussiaas a rare native occurrence worldwide
Why it is that colour
Metallic, tarnishing rapidly to a dull oxide film that then protects the metal beneath.
Safety
A cumulative neurotoxin with no established safe level of exposure, and particularly damaging to developing brains. Metallic lead is less readily absorbed than lead salts but is still hazardous, especially as dust or fume. It is soft enough to leave a mark on paper, which tells you how readily it sheds.
Where it comes from
Mined from galena; over half of world lead supply is now recycled, mostly from car batteries. Lead smelting has left severe contamination at sites worldwide.
Historical use
Roman plumbing takes its name from it, and so does the plumb line. Lead pipes, lead glazes, lead cosmetics, lead paint, lead solder and tetraethyl lead in petrol have between them produced one of the largest chronic exposures in history. Leaded petrol was finally eliminated worldwide in 2021.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
What is attributed to it, and since when
Saturn in the alchemical scheme — the heaviest, dullest, slowest and basest of the metals, associated with time, melancholy and limitation. Turning lead into gold is the shorthand for the whole alchemical project, and the pairing is deliberate: the basest metal and the most perfect one.
Described, not endorsed. Dating a claim is not the same as assessing it — but an association that first appears in a book published in 1985 is not an ancient inheritance, whatever the label says. A sincere account of feeling better is compatible with the stone doing nothing — see the placebo effect.
Worth knowing
The story of tetraethyl lead is worth knowing in a collection that spends a lot of time on how claims get established. Lead was added to petrol from 1923 to stop engine knock. Its danger was known immediately — workers at the plants that made it died or went mad within months, and the process was briefly suspended in 1925 — and the industry commissioned reassuring science and won the argument.
Clair Patterson, a geochemist trying to date the age of the earth, found in the 1950s that his samples were contaminated with lead from the atmosphere, and eventually established that atmospheric lead had risen enormously since 1923. He spent the rest of his career being attacked by the industry and its funded researchers, and he was right. The phase-out began in the 1970s and finished in 2021.
It is a useful case because nothing about it was mysterious. The harm was known at the start, the counter-evidence was manufactured, and the resolution took a century.
Identity checked against IMA-CNMNC master list, June 2025.