silicates
Chrysotile
Mg3Si2O5(OH)4
- Also known as
- white asbestos
- Crystal system
- monoclinic
- Hardness
- 2.5–3 on the Mohs scale
- Lustre
- silky
- Colour
- White, pale green, grey, fibrous
- Where it forms
- In serpentinite, as cross-fibre veins where the fibres grew perpendicular to the fracture walls.
- Chiefly from
- Quebec, CanadaRussiaKazakhstanItaly
Why it is that colour
Essentially colourless magnesium silicate; the silky appearance comes from the fibre bundles.
Safety
White asbestos, and by far the most widely used of the asbestos minerals — historically around ninety-five per cent of all asbestos in use. It is a recognised human carcinogen causing asbestosis, lung cancer and mesothelioma. It remains legal to mine and use in some countries. Do not handle, cut, or disturb fibrous material. This is a genuine hazard rather than a precautionary one.
Where it comes from
Russia and Kazakhstan remain major producers. Quebec, once the world centre, ceased production in 2012 and Canada banned asbestos in 2018. The town of Asbestos in Quebec voted to rename itself Val-des-Sources in 2020.
Historical use
Its resistance to fire made it valuable in the ancient world — Pliny describes cloth woven from it, used as a cremation shroud and cleaned by throwing it in the fire — and in the twentieth century it went into insulation, cement, brake linings and roofing on an enormous scale. The World Health Organization attributes over two hundred thousand deaths a year to occupational asbestos exposure.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
Worth knowing
Chrysotile is one of the serpentine group, and its difference from its harmless relatives is purely structural. Lizardite forms flat sheets. Antigorite forms corrugated ones. Chrysotile's sheets roll up into hollow tubes, because the magnesium layer and the silicate layer have slightly different natural spacings and the mismatch curls them.
Rolled into tubes, the mineral is a fibre. As a fibre, it is inhalable, and it does not dissolve. That is the whole difference between a green ornamental stone and two hundred thousand deaths a year.
Identity checked against IMA-CNMNC master list, June 2025.