lasitteissa

Lasitteissa is the Finnish inessive plural form of lasite, a glaze used on ceramics. The term is used in ceramic technology, materials science, and archaeology to refer to glaze layers or the glazes themselves in contexts dealing with multiple pieces or examples.

In ceramics, lasite is a vitreous coating fused to the surface of a ceramic body during firing. Glazes typically consist of silica as a glass former, fluxes that lower the melting point, and colorants or opacifiers. The glaze forms a smooth, glassy layer that provides color, waterproofing, and a specific surface texture. The properties of lasitteet depend on the glaze recipe, the firing temperature and atmosphere, and the nature of the clay body to which the glaze is applied. Glaze application methods include dipping, brushing, and spraying, and the glaze is usually applied to bisque-fired ware before the final firing.

Within lasitteissa, practitioners and researchers study color development, microstructure, and the interactions between glaze and substrate. Common topics include the distribution of colorants, crystallization within the glaze, and defects such as pinholes, crazing, blistering, or crawling. Analytical approaches range from optical microscopy to electron microscopy and spectroscopy, used to understand glaze composition, thickness, and bonding to the ceramic body. In conservation and archaeology, examining lasitteissa can reveal historical techniques, provenance of materials, and trade networks.

See also: lasitus, lasite.