Asbestos is a generic term given to several naturally occurring silicate minerals
The common ones are :-
Chrysotile White asbestos
Amosite Brown asbestos
Crocidolite Blue asbestos

Three others found in the UK are actinolite, anthopholite and tremolite - there are believed to be some 24 other types worldwide.

Whilst the fibres in their natural state have colour, when they are added to cement (etc.), their individual colour is lost ie. grey looking asbestos cement may contain one, two or more types of asbestos.

Some materials thought to contain asbestos, can often be fibreglass or other substances. The asbestos content (types of and concentration), can only be established by analysis in a specially equipped laboratory.

Asbestos use in the UK peaked in 1973 - but was only banned outright in the UK on the 24th November 1999.

A few buildings have been stripped of asbestos - and safer materials used as replacements. Most of the asbestos ever used is still in place in what is arguably the majority of the buildings in the UK - much of it's presence remaining undetected.