Crocidolite asbestos is a form of asbestos known to cause mesothelioma. Crocidolite asbestos is an amphibole. Its structure is similar to that of chrysotile in that it occurs as finely textured hair-like fibers that occur in naturally formed bundles. Crocidolite fibers are somewhat brittle but are flexible enough usually to bend beyond 90 degrees before breaking. These fibers are commonly curved, but straight fibers and bundles are also found. In crocidolite iron is the predominant mineral over magnesium and aluminum. It is called "blue Asbestos" because of its color that ranges from pale green to indigo to Prussian blue. Crocidolite is harder than the other varieties of amphibole asbestos.

In the production of commercial products, crocidolite asbestos was the least used of the various forms of asbestos. Approximately 10% of the asbestos used in the United States was crocidolite.