Alabaster
The alabaster is a variety of Gypse (hydrated sulfate of Calcium) which is presented in a massive form, contrary to the selenite , or “glossed spar”, which is a fibrous variety. Its name comes from the old Greek αλάϐαστρος/ alabastros , which indicated a vase without handle, alabaster being used to work vases with perfume without handle.
Alabaster, like the gypsum, is rayable with the Ongle (hardness Mohs 1,5 to 2). Its crystalline system is of monoclinical type. This variety of gypsum with fine grain is extracted in particular in English careers or from Toscane. Alabaster is employed like Pierre decorative. Its tendreté allows to carve it in elaborate forms. Water soluble, it cannot be employed in outside.
Calcite, false alabaster
Calcite is the “alabaster of Old” or “alabaster of the Bible” or “alabaster of the East”, because the first objects which we know out of alabaster come from the Far East. It was very required for the manufacture of small bottles of perfume or of ointment, called will alabastra - possible origin of the word “alabaster”.
Alabaster was also employed for the Egyptian canopes and other types of sacred vessels or funerary. A sarcophagus carved of only one holding in calcite appears thus in the collections of the Sloane museum, with London. He was discovered by Giovanni Belzoni in 1817 in the tomb of the Pharaon Séthi I {{er}}, not far from Thèbes. He was bought by Sir John Sloane after being proposed, without success, with the British Museum. The stone was extracted close to Thèbes, with Akhetaton, city which the Greeks re-elected Psinaula or Alabastron .
Cut out into thin layers, alabaster is sufficiently transparent to be used like glazes for small windows. It was employed with this use in certain medieval churches , particularly in Italy. More recently, it was resorted there abundantly for the Notre-Dame cathedral of the Angels of Los Angeles, devoted in 2002. A specific device of cooling makes it possible to prevent the panels from becoming opaque under the effect of heat.
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