Substance/material subclass?

[dlutz2]

Are there plans in a future version of CCO to include a subclass of material entity for substances/materials? We are mapping in a legacy coding scheme which has large number of elements of the pattern: XX_facility is a cco:Facility that extracts/processes/refines/stores/consumes ZZ_Material

It would be convenient to have a defined class to hook our extensive lists of raw materials, chemicals etc.

thanks