Selenite

Selenite is one of the morphological varieties of the gypsum mineral.

It differs in the fine-fiber structure of aggregates. Translucent. Name from Greek. selene - Moon, due to the special nature of light reflection, reminiscent of the moonlight (not to be confused with the kind of feldspars - the moon stone !!!). Selenite is a parallel-columnar aggregate of the third type (A.G. Zhabin, 1979), forms veins of parallel-fibrous structure in clayey sedimentary rocks and marl sandstones, with a fiber length of up to 10-15 cm. It grows in cracks when they are extended, or he spreads cracks due to crystallization pressure. Selenite fibers are oriented perpendicular to the walls of the cracks. Often contains inclusions of clay (in the form of veins perpendicular to the fibers and lenticular grooves), sand, hematite, sulfur, organic substances (bitumen, etc.).

In English sources, unlike domestic ones, the term "selenite" is often used to refer to transparent crystals of gypsum, while the name "gypsum" applies to all its varieties, including translucent massive aggregates.

The color of pure selenite is white, but more often it is colored with impurities in yellowish, bluish or pinkish hues. Shines through. Silky shine and a beautiful iridescent optical effect of moving an iridescent light strip on a polished surface or chip when turning a stone (“iridescence” or “cat's eye effect”) are characteristic, which is similar to that of a cat or tiger eye. The effect arises as a result of the scattering of light rays on thin parallel surfaces of the boundaries of fibrous individuals. This effet arises due to the parallel arrangement of numerous fine fibers densely fused with each other, is very pronounced in selenite, and appears only on surfaces parallel to the fibers. Soft, hard 2. Selenite is much stronger than ordinary gypsum, because characteristic of gypsum crystals, a very perfect cleavage is not observed, but it splits along the fibers, perpendicular to the base of the aggregate.

It is used as an inexpensive ornamental stone for the manufacture of carved art and household products - sculptures, souvenirs, beads and inserts. Selenite owes its appearance and development to the well-known stone-cutting industry in the Urals, the Ural Stone-cutting Plant, the Kungur Artistic Works Plant and the Kungur Stone-Cutting Art School are engaged in processing this stone. Artifacts made of iridescent golden selenite are represented in many museums and have been exhibited at many Russian and international exhibitions.

Selenite is easy to sand and well polished. But in products it can quickly overwrite and lose polishing due to low hardness, and then requires new polishing. In the ancient world, selenite was a symbol of modesty and spiritual purity, and the priestesses of the Moon goddess used it for cult purposes. Large deposits of selenite are known in Russia - in the Urals in the Perm Territory (Kungursky district, on the slopes of the Iren River), abroad - in the USA, Australia, Canada, Egypt, France, Germany, Tajikistan.