Which of the following is NOT one of the three most common types of asbestos fibers?

The three most common types of asbestos fibers are chrysotile, amosite, and crocidolite. Chrysotile, often referred to as "white asbestos," is the most prevalent form used in a variety of products due to its flexibility and resistance to heat. Amosite, known as "brown asbestos," is known for its high tensile strength and is often found in cement sheets and thermal insulation products. Crocidolite, or "blue asbestos," is recognized for its high resistance to heat and is typically utilized in more hazardous materials.

Antophyllite, while recognized as an asbestos type, is significantly less common in commercial use than the three mentioned above. It has limited applications and is not typically encountered in building materials, which is why it is the correct choice for this question. Understanding the prevalence and usage of these asbestos types is key for inspectors, as it helps in identifying potential asbestos-containing materials in buildings.