Molecular Formula: Na₂(Fe,Mg)₅Si₈O₂₂(OH)₂
Mohs hardness: 5.0–6.0
Specific gravity: 3.0–3.4.
Water solubility: Insoluble

Asbestos, crocidolite (12001-28-4) was named after German explorer Emil Riebeck (1853-1885).

Asbestos, crocidolite (12001-28-4) was found on the island of Ailsa Craig in western Scotland, and it can be used in the manufacture of curling stones.It was also used for the facing stones of the Canton Viaduct from Moyles Quarry  now part of Borderland State Park in Massachusetts.

NTP 10th Report on Carcinogens. IARC Cancer Review: Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 14 (1977),p. 11.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) , IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 2 (1973),p. 17.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 14 (1977),p. 11.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . EPA Genetic Toxicology Program.

Confirmed human carcinogen with experimental carcinogenic, neoplastigenic, and tumorigenic data by inhalation. Human mutation data reported.

OSHA PEL: TWA 2 million fibers/m³; CL 10 million fibers/m³; Cancer Hazard
ACGIH TLV: TWA 0.1 fibers/cc; Confirmed Human Carcinogen
DFG MAK: DFG TRK: (Fine dust particles that are able to reach the alveolar area of the lung) crocidolite: 0.05 × 10⁶ fibers/m³ (0.025 mg/m³) (definition of fiber: length greater than 5 µm; diameter less than 3 µm; length/diameter greater than 3:1, equivalent to 1 fiber/cc)
NIOSH REL: (asbestos): 0.1 fb/cc in a 400 L air sample
DOT Classification:  9; Label: CLASS 9

For occupational chemical analysis use NIOSH: Fibers, 7400; Asbestos Fibers, 7402.

Some forms of Asbestos, crocidolite (12001-28-4)'s are asbestiform, notably crocidolite, also known as blue asbestos.It is a sodium-rich member of the amphibole group of minerals. It crystallizes in the monoclinic system, usually as long prismatic crystals showing a diamond-shaped cross section, but also in fibrous, bladed, acicular, columnar, and radiating forms.Long term occupational exposure to the dust can result in lung cancer.Cleavage is perfect, two directions in the shape of a diamond; fracture is uneven, splintery. It is often translucent to nearly opaque.The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment.