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other names: /
mineral class: Hydrous sulfates without foreign anions
chemical formula: CaSO4 · 2 H2O
Chemical elements: Calcium, sulfur, oxygen, hydrogen
Similar minerals: Plaster
colour: white, yellow, pink, brown, gray
shine: Glossy glass, pearlescent
crystal structure: monoclinic
mass density: 2,2
magnetism: not magnetic
Mohs hardness: 1 - 2
stroke color: White
transparency: transparent to translucent
use: Arts and crafts
General information about the alabaster:
alabaster describes a natural stone, which belongs as a variety of gypsum to the calcium sulfates. The alabaster owes its name to the Egyptians, to whom it was available as building material in huge quarries. Presumably, the name goes back to Albastron, that ancient city, near which were huge deposits of natural stone. The Greek naturalist Theophrastos of Eresos was the first to mention alabaster in his writings after visiting Albastron and seeing the works of art and everyday utensils made from them. But it is also possible that the Egyptian fertility goddess Bastet has been named after the alabaster.
Alabaster is similar in appearance to marble and usually has a white color. Yellow, light pink, brownish and gray variations with cloudy or veined patterns are also common. The stroke color of the alabaster is always white. The stone forms prismatic, often to twins connected crystals as well as massive, platy or fibrous aggregates. Alabaster shows a glassy or silky sheen and a transparent through the crystal water usually transparent. He is from mussel or uneven fracture. With a maximum Mohs hardness of 2 alabaster is very soft and of perfect cleavage. As a bad heat conductor, alabaster is significantly warmer to the touch than marble. The effect of heat evaporates the crystal water contained inside the alabaster, giving the stone an opaque appearance. The melting point of the rock is 1400 degrees Celsius.
Occurrence and extraction:
Alabaster and gypsum were created about 27 million years ago due to the evaporation of the primeval sea, leaving large-scale lakes with high lime deposits. As these lakes gradually evaporated in the course of Earth's history, highly concentrated salts were formed, which eventually developed into calcium sulfate in the form of gypsum and alabaster. Today, these two natural stones are mined in large deposits a few meters below the surface of the earth, but can also be found in depths of up to three hundred meters.
Alabaster is primarily produced in large parts of central and southern Europe, with the best quality stones from Spain and Italy. There are also economically significant deposits in the United Kingdom, some Eastern European countries, the United States and Japan.
Use by humans:
A popular material for sculptors, the alabaster looks back on a history spanning several millennia. Even the ancient Egyptians made of alabaster statues and statuettes and elaborate vessels for make-up. Since ancient times, the rock is considered a royal material. Since alabaster is of porous structure, it is excellent for dyeing. In Europe alabaster was a popular material for the design of church elements, reliefs and lifelike depictions of rulers from the early Middle Ages up to Scandinavia. To this day, precious bowls, vases, lamps and sculptures are made from alabaster.