Flakes of raw vermiculite concentrate are micaceous in appearance and contain interlayer water in their structure. When the flakes are heated rapidly at a temperature above 870° C, the water flashes into steam, and the flakes expand into accordion-like particles. This process is called exfoliation, or expansion, and the resulting lightweight material is chemically inert, fire resistant, and odorless. In lightweight plaster and concrete, vermiculite provides good thermal insulation. Vermiculite can absorb such liquids as fertilizers, herbicides, and insecticides, which can then be transported as free-flowing solids.

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Annual Publications

Mineral Commodity Summaries

• Vermiculite
    PDF Format:    | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |2012 |2013 |2014 |2015 |2016 |2017 |2018 | 2019 | 2020 | 2021 |
• Appendixes

Minerals Yearbook

• Vermiculite
    PDF Format:    | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 |
    XLS Format:
       | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 tables-only release | 2019 tables-only release |
• Archive
       | 1932-1993 |

Special Publications

• Historical Statistics for Mineral and Material Commodities in the United States 
  Data Series 140
  • Vermiculite