The most appropriate Jesmonite product for decorative elements within a wet or external environment would be AC730.
Jesmonite AC730 is a two pack water based, micro-concrete composite material. It is a shrinkage-compensated material of low permeability and is durable in all conditions, including water features.
Please be aware that AC730 is a decorative material and not designed for structural purposes. To create AC730 products which achieve a greater strength to weight ratio, I would recommend they laminate AC730 using x3 layers of Jesmonite Quadaxial Glass with minimum laminate thickness of 12mm.
Once the AC730 is de-moulded and fully cured (demoulded and left for 24 hours) it would then need to be fixed or bonded onto a substructure or frame system.
AC730 contains a blend of decorative aggregates and pigments to achieve a range of stone and concrete effect surface finishes. The AC730 surface will behave in the same way as a concrete or natural stone surface.