Lamps are commonly used in households as reading or table lamps. They generally consist of two parts: the stand and the shade. A variety of materials is used in making the shades and stands. With the passing of time, different materials have come to be used for making lamp stands and shades. These range from skin to wood, silk to cotton etc. for the shades. Materials for lamp stands include wood, stone, metal, marble, alabaster, etc.
Since ancient times, alabaster has been commonly used in making lamp stands. Over the years, references to the material have changed, though it still retains the same aesthetic values. Alabaster, also called “satin spar”, is the generic term for two distinct types of material: gypsum and calcite. Alabaster used nowadays is gypsum, while alabaster used by the ancients was calcite. The two materials are distinctly different from each other because of their hardness. Gypsum, a hydro sulfate of calcium, is extremely soft, so much so that it can get scratched even by finger-nails. The hardness of gypsum is 1.5 to 2.
The other material regarded as alabaster, calcite (hardness 3), is not as soft as gypsum. However, it too can be easily scratched with a knife. Since, calcite is a carbonate of calcium it effervesces in coming in contact with hydrochloric acid. Gypsum remains unaffected by the acid. |
