It is believed that the mineral, now known as vermiculite, was originally observed in Worcester, Massachusetts, in 1824. When exposed to a flame, the mineral would expand into a variety of fanciful forms resembling small worms. Because of this peculiar property, Thomas H. Webb gave it the name vermiculite, or worm breeder.

For about 100 years after its discovery, vermiculite was not of commercial significance. However, in 1923 a deposit in Libby, Montana, was developed for commercial production, as was a deposit in the Enoree, South Carolina (SC), region in 1946. Both these operations were started by the Zonolite Company (Chicago, Illinois) and Grace Construction Products entered the vermiculite business in 1963 with the acquisition of the Zonolite Company. With this acquisition, Grace purchased both the Libby and Enoree mines as well as the largest expanding facility in the United States at the time.

Due to declining demand, Grace chose to close the Libby facility in 1990. As the first mine to close in Montana since the inception of the permitting process in 1971, the project came under close scrutiny from the Mining Industry as well as various regulatory bodies. With the removal of all man made equipment and a comprehensive mine reclamation, the project was awarded the 1st In Pursuit of Excellence Award by the mining industry for efforts that exceeded standard practices of the day.

With the commercial development of vermiculite, Grace pioneered end-use applications such as spray-on fire protection, lightweight insulating concrete, various soil mixes and soil amendments, and animal feeds. Over the years, Grace has sold these businesses to various parties that continue to successfully use vermiculite and vermiculite-based technology.

Currently, Grace is a raw material supplier of both vermiculite concentrate and expanded vermiculite products. All mining activities are in the Enoree, SC area. Grace is the largest producer of vermiculite in North America and the only vertically integrated supplier of both ore concentrate and expanded vermiculite. Vermiculite expanding operations are located in:

Enoree, South Carolina
Pompano, Florida
Phoenix, Arizona
Ajax, Ontario, Canada
Winnipeg, Manitoba, Canada
Edmonton, Alberta, Canada

Grace Specialty Vermiculite completed construction of a state-of-the-art MicroLite® dispersion plant in Enoree, SC, in 1998. MicroLite® is a chemically-exfoliated form of vermiculite with unique gas barrier and anisotropic film characteristics.

In addition to vermiculite, Pompano, Ajax, Winnipeg, and Edmonton also carry a wide range of expanded perlite products.