What is the difference between calcined and vitrified clay?

Both calcined clay and vitrified clay are made from naturally occurring materials found in geographic locations throughout the country. After these materials are mined, they are processed and heated at high temperatures to stabilize their physical structure. This protects the physical integrity of the individual particles against the breakdown caused by moisture or surface management practice. These materials have a variety of applications on sports fields including topdressing infield skin areas, amending soils to reduce compaction and/or manage moisture, and absorbing excess moisture on playing surfaces.  more