"Definition of the Expansion/Exfoliation Ratio: Asbury Graphite’s definition of expansion ratio is the quotient of expandable graphite’s post heating expansion volume and original sample mass. The “units” are reported simply as “expansion ratio”, “exfoliation ratio”, or “heat expansion”. If one performs a dimensional analysis on the expansion quotient, the units are volume/mass, which reads like a specific volume. Due to certain complications such as volatile content the “expansion ratio” is not a specific volume."
It's a really educational page, and explains why an expansion ratio of 1000x is really desirable for certain applications.
