Description

Gypsum
Raw materials and description
The natural gypsum stoneis a mineral formed by di-hydrated calcium sulphate. In its crystalline structure, there are two
water molecules by one of calcium sulfate. Put under calcination (******0 ºC), it releases part of the crystal water,
obtaining itself a semihydrateof calcium sulphate or burnt gypsum, that being mixed with water, is solidified again
and crystallized, reconstituting the original rock in its natural state. The plaster is a gypsum variant, finer, white, and of
greater hardness than normal gypsum, employed as the material of ornamentation and with other stucco additives.
Black gypsum is the traditional name for an artisan semihydrate, that is obtained from natural mineral. It contains
more impurities than white gypsum, it is of greyish color, and suitable for the first layer in the inner plasters of the
constructions. Its also suitable to use in mortars.
Dead gypsums are those submissive to industrial processes and higher temperatures of calcination, from **0 to **0
ºC or superior (if so by-products of the industry of cement and with chemical additives and retarders), thus form different
more or less insoluble anhydriteclasses, of greater resistance, little porosity and incapable to regulate environmentally
humidity, with the consequent danger of condensation and formation of fungi.
Due to this, works of restoration and eco-building, as gypsum-lime or plaster stuccos, are only due to use
natural burnt gypsums:
Given its porous structure, crystallized natural gypsum contributes exceptional bio-climatic properties. Its
excellent qualities of isolation and hygrometric regulation, directly do of it an irreplaceable material in the
restoration and eco-building, being used directly on the walls or like mortar. Its high plasticity confers to it
an infinity of possibilities in decoration. By its bio-climatic and natural properties, the natural gypsum coatings
contribute to comfort, creating a healthy and balanced climate and atmosphere in livings and other interior
spaces.