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Most Common Types of Asbestos

Serpentine and Amphiboles are the two main forms of asbestos. Serpentine asbestos is made of curly and flexible fibers. Amphibole asbestos is made of thin rod or needle like fibers. Due to its flexibility, serpentine is the more commonly used type of asbestos.

• Amosite, commonly referred to as “brown asbestos,” is an amphibole originating in S. Africa. This type of asbestos is most frequently used as a fire retardant in insulation products as well as in ceiling tiles.
• Crocidolite Asbestos also referred to as the “blue asbestos” is an amphibole that is commonly found and mined in parts of Africa and Australia. Amosite and crocidolite are the most common types of amphibole asbestos.
• Tremolite Asbestos is an amphibole that has been found in the United States. It is most commonly associated with W.R. Grace’s “Zonolite” insulation. “Zonolite” is comprised mainly of vermiculate, which mineral is commonly found in the earth alongside asbestos. Until 1990, over 80% of vermiculite mined in the United Sates came from W.R. Grace’s mine in Libby, Montana, which was contaminated with Tremolite asbestos. 
• Anthophyllite Asbestos is one of the more rare forms of amphibole asbestos. It was not widely used in manufacturing, but it was commonly used in caulks.
• Actinolite Asbestos is one of the lesser used forms of amphibole asbestos. It is bright green in color, and the nephrite variety of actinolite is one of the two minerals called Jade. Actinolite was not widely used in manufactured products, but may be found in some types of insulation.