Native Clay Posted on 9th December 201515th May 2021 by ThePD (The Project Definition) A Native Clay is the finely grained natural rock or soil material incorporated into a so-called native-solids mud. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Substance and tagged solid. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.