asbestos - tremolite (amphibole) asbestos - teaching hand specimen of fibers in a screw-cap pyrex tube

Asbestiform tremolite from the McIlroy Mine, Inyo County, California.

Tremolite is a calcic amphibole which forms a solution series with actinolite and ferro-actinolite. The ideal formula is Ca₂Mg₅Si₈O₂₂(OH)₂ .

The McIlroy Mine exploited an asbestos vein in the Silurian to early Devonian Hidden Valley Dolomite. It was active in the mid-1900s and is now abandoned.

Tremolite is most often found in metamorphosed dolomitic limestones. Its crystals can grow as fine fibrils that are considered asbestiform. Asbestos is a commercial term used to describe the fibrous material. The form of asbestos most commonly used and encountered is the serpentine mineral chrysotile. Amphibole asbestos such as this is much less common.

The asbestos from the McIlroy Mine was mainly sold to the Powhatan Mining Company for use in crucible filters. This mine is the probable source of fibers that served as reference standards used since around 2000 by the Health and Safety Laboratory (UK). Fibers from the McIlroy Mine have been available as standards from NIOSH since 2014.

A customer commented: "Fantastic tremolite asbestos samples. Purchased for an upper division university course on Energy and Mineral Resources. These samples show all the properties I want the students to see."

Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with the least expensive shipping. A link in that invoice will bring you back to checkout, no hassle. 

Shipping: By Priority Mail or USPS Ground Advantage, whichever is cheaper, unless we find a better rate. Click > here < for shipping rates. Use back button to return to this page.