Serpentinite

Serpentinite is a metamorphic rock made up mostly of serpentine-group minerals (such as chrysotile, antigorite, and lizardite). It forms when iron- and magnesium-rich rocks from deep in the Earth react with hot water, producing a slick, greenish rock that often contains veins of fibrous chrysotile asbestos. Serpentinite is the primary natural source of chrysotile, the most commercially used form of asbestos.

Origin

The name comes from the Latin serpentinus, meaning "serpent-like," referring to the rock's mottled green color and scaly surface that resembles snakeskin. The term has been used in geology since the 1500s, and serpentinite was formally recognized as a distinct rock type in 19th-century mineralogical literature.

Significance in Asbestos Context

Nearly all chrysotile asbestos ever mined came from serpentinite deposits, including the historic mines of Quebec (Thetford, Asbestos/Val-des-Sources), California (New Idria, Coalinga), Russia (Ural Mountains), and Italy (Balangero). When experts trace the geological origin of fibers found in a patient's lung tissue or in a product, identifying serpentinite-derived chrysotile can help link exposure to specific mines, products, or worksites. Serpentinite also matters in non-occupational cases: people living near serpentinite outcrops or working with serpentinite road base, crushed stone, or landscaping rock can have environmental exposure to naturally occurring asbestos, which has driven litigation in California and other states with extensive serpentinite belts.

Example Sentence

The plaintiff's geologist testified that the chrysotile fibers recovered from the patient's lung tissue had mineral characteristics consistent with serpentinite from the Quebec mining belt, matching the insulation products used at his former workplace.

Related Terms

Chrysotile, Ophiolite, Naturally Occurring Asbestos, Provenance Analysis, Antigorite, Lizardite

Notes

• If you lived, worked, or went to school near a serpentinite outcrop (especially in California, Pennsylvania, Vermont, or the Appalachian belt), document the address and dates. Environmental exposure to naturally occurring asbestos in serpentinite can be a viable claim.
• Ask your legal team whether fiber-burden or tissue digestion analysis is appropriate; the mineralogical "fingerprint" of serpentinite-derived chrysotile can sometimes be linked to specific mining regions or products.
• Preserve any records of home renovations, road work, or construction projects that involved crushed rock, gravel, or fill. Serpentinite is sometimes used as aggregate and can release fibers when disturbed.
• For occupational exposure, identify whether the products you worked with (gaskets, brake linings, joint compound, insulation) used chrysotile from serpentinite sources, as nearly all chrysotile products did.