About Asbestos
Asbestos is divided into two primary classes: Amphibole and Chrysotile. Both share heat-resistant properties that make them valuable to the construction industry. They are both fibrous, insoluble, odourless and tasteless. They differ in chemical structure and colour.
“Amphibole versus Chrysotile”
Brown Amosite and Blue Crocidolite are asbestos minerals in the Amphibole class. White Serpentine is the only Chrysotile.
Amphiboles are sharp, straight, needle-shaped, double-chain silicates (inosilicates) with metal atoms connected to the base unit. They are more friable than Chrysotiles. Chrysotiles are formed in a curved, flexible sheet.
“Brown Amosite”
Brown Amosite is also known as Grunerite, Fibrous Cummingtonite or Mysorite. It has a variety of structures with the following chemicals being present: Silica, Ferrous Oxide, Ferric Oxide, Manganous Oxide, Calcium Oxide, Magnesium Oxide, Sodium Oxide, Potassium Oxide, Carbon Dioxide and Water Crystals.
Brown asbestos is made of coarse, solid fibres formed in an alternating sequence of an octahedral cation oxide layer and hexagonal silica tetrahedra layer. These are loosely bonded in a linear double chain. The smallest fibres have an approximate diameter of 0.1 microns. Amosite is found in these colours – brown, yellow, gray or green.
“Blue Crocidolite”
Blue Crocidolite is found in many formulas with these basic chemicals present: Silica, Ferrous Oxide, Ferric Oxide, Manganous Oxide, Calcium Oxide, Magnesium Oxide, Sodium Oxide, Carbon Dioxide and Water Crystals.
Crocidolite asbestos is in the form of coarse, solid fibres formed in an alternating sequence of an octahedral cation oxide layer and hexagonal silica tetrahedra layer. These are loosely bonded together in a linear double chain. The smallest fibres have an approximate diameter of 0.08 microns. The colours for Crocidolite are blue, purple or green.
“White Chryosotile”
White Chryosotile has the nickname, Serpentine, due to its silky, curly fibres. This Serpentine asbestos is easily spun and woven into fabrics.
Although there are a variety of formulas involved, the following chemicals form the Serpentine asbestos – Silica, Alumina, Ferrous Oxide, Ferric Oxide, Calcium Oxide, Magnesium Oxide, Carbon Dioxide and Water Crystals.
White asbestos fibres are hollow. They form in tightly-packed, rolled-up sheets of alternating hexagonal silica and brucite-like sheets of octagonal magnesium hydroxide. The tight fit of the sheets gives the fibres their curled shapes. These sheets do not have a very strong bond; they can be subdivided easily.
The smallest fibres have an approximate diameter of 0.01 microns. Serpentine asbestos can be found in white, gray, green or yellow colours.