Six minerals were regulated as asbestos and three of them account for almost everything in a British building: chrysotile, amosite and crocidolite, known in the trade by the colours white, brown and blue. The colour names are a rough guide to the mineral and a poor guide to the material, because a white asbestos cement sheet and a white asbestos textured coating behave entirely differently. What matters far more than the type is the material it is bound into and the condition it is in.
Chrysotile, the white one
Chrysotile is the serpentine mineral and by far the most used. It is in cement sheeting, textured coatings, floor tiles, gaskets, rope seals and countless mouldings. It was the last type to be banned in the United Kingdom, which is why buildings and products from the 1990s can still hold it, and why a house finished shortly before the ban is not automatically clear.
Amosite and crocidolite: brown asbestos and blue asbestos
Both are amphibole minerals and both are more hazardous than chrysotile. Amosite turns up in insulating board and some insulation; crocidolite in sprayed coatings, lagging and some insulation products. Neither is reliably identified by colour in a real building, because the products were painted, aged and dirty long before anyone looked at them.
Why the colour is not the answer
The names describe the mineral in its raw state, not the finished product. Asbestos cement made with chrysotile is grey. Insulating board made with amosite is off white. Sprayed coating made with crocidolite is often painted cream. Judging by colour is how people conclude a material is safe when it is not, and the analysis certificate names the mineral properly.
Does the type change what you must do
Not directly. The regulations apply to all types, and what decides whether work is licensable is the material and the work rather than the mineral: insulation, sprayed coating and most work on insulating board are licensable whatever type they contain. The type appears on the analysis certificate because it is a fact worth recording, not because it changes the rules.
Questions people ask about three types of asbestos
How many common types of asbestos are there?
Six minerals were regulated. Three are common in buildings: chrysotile, amosite and crocidolite. The other three, anthophyllite, tremolite and actinolite, appear mainly as contaminants.
Is crocidolite asbestos colour a reliable guide?
Crocidolite is blue in its raw mineral form, which is where the trade name comes from. In a finished, painted, decades-old building material the colour is no guide at all.
Is white asbestos less regulated?
No. All types are covered by the same regulations, and the licensing rules follow the material and the work rather than the mineral.
What are the three main types of asbestos?
Chrysotile, amosite and crocidolite, known in the trade by the colours white, brown and blue. Six minerals were regulated as asbestos, and these three account for almost everything found in a British building.