Wikipedia
Shikkui is an ecological nontoxic Japanese lime plaster primarily made out of hydrated lime and calcium carbonate coming from reprocessed eggshells. It is mainly used for surface coatings of walls and ceilings in housing construction.
This material is reputed to achieve a notable range of traditional and modern finishes, including a full range of Venetian stucco and stone effects. Shikkui finishes allow a thin two-coat application, and their elasticity provides good stress-crack resistance. The color and texture of a finishing can be individually customized using a variety of diluted color pigments.
The coatings are highly porous and naturally antiseptic, so indoor air quality is actively improved for healthier spaces. Shikkui coatings are also said to be humidity-regulating, fire-resistant, antistatic (preventing dust accumulation), hypoallergenic, antifungal and mold resistant.
Shikkui surface coatings become harder as time passes, as they are continuously absorbing CO.