White foam
White foam is a suspension solution formed through aggregate, whisperling stomach acid and a unique mucus formed in the roof of the whisperling mouth. The stomach acid is tinted by the digested inorganic matter consumed before the beginning of the process, and the acid within the gut breaks the bonds of the overall structures into a dissolved aqueous slurry.
When combined with the mucus in the reguritation, the white foam is produced. The foam exists in a gel-like consistency, but is rapidly exothermic, seeking to find its solid state as the mucus and water molecules react and form hetrogeneous crystals that are laced with the metal ions, sillicates, and other interstitial irregularities.
Uses
In gel form, the white foam is laced with sand to make a sticky substance that whisperlings use as a marking for their official documents (hence why they use the term white foam for their own version of bureaucracy).Its other main use is as a building material - larger stones and grit are added to this substance, which is made temporarily water stable with massive cooling from biochemical coolers (Or used as is in aerobic environments). The solution is applied to surfaces, either as a binding agent, or a rendering agent, its chemical hardening providing it with solid adhesive properties.
Properties
Material Characteristics
The gel-foam is viscous, similar to septum, and due to its temporary life outside of the gullet of the whisperling that makes it, less well explored chemically by the nightbloom that have looked into it.
Solid white foam is strong along one face of its construction, but sheers easily into irregular sheets along the other facing. With this in mind, complete structures are often not made from white foam alone, but acting as mortar, rendering or binding for complex structures made of homogeneous building blocks - often coral.

Very cool indeed. On the question of marking documents, is there a way to make the marking unique, say a particular proprietary mixture of sand lacing it or something that could allow it to be a signature of sorts?
Interesting idea I will investigate in the mk 2