Gems of the world
Precious and semi-precious stones
Precious and semi-precious stones known to man for nearly 10,000 years. Since ancient times, for the rich strata of the population, they served as a symbol of social status. Later rulers prove their authority by insignia, adorned with precious stones.
In our days, precious stones flaunt not only to demonstrate the wealth, they are for my own pleasure, to enjoy their beauty and harmony.
Of course, now with the purchase of jewelry often plays the role of a preference for particular stones. Before when people were less well versed in the natural Sciences, precious stones wrapped in mystery, with something unearthly. So they almost always played the role of amulets and talismans.
Most precious and semi – precious stones, minerals. In line with this, the history of precious and semi-precious stones is the history of minerals. Some minerals kristallizuetsya of fiery liquid alloys and gases in the bowels of the Earth or from lava of volcanic origin. Other precipitate from water solutions or grow with the participation of organisms near the surface or on the surface of the Earth. And finally new minerals are formed by recrystallization of existing under the influence of high pressures and high temperatures in deeper layers of the crust.
Deposits of precious stones
The origin of the rocks containing the gems, there are igneous, sedimentary and metamorphic deposits. It is better to speak about the primary and secondary fields.
The primary fields of productivity is often not very high. In the extraction of precious stones along the way, you have to excavate a large number of "empty" breed.
In the secondary deposits of precious stones displaced from their places of origin and are concentrated in the so-called placers. Depending on the means of travel or location we distinguish fluvial (alluvial), lake (Limnology), marine coastal (intertidal) or wind (Eolian) sediments.
Classification of precious gems.
Precious and semi-precious stones combined into 10 classes:
- Elements. Diamond, gold, sulfur, silver.
- Sulphides. Algodonite, bornite, breithauptite, chalcocite, cobaltite, covellite, greenockite produce, copper pyrite, marcasite, millerite, melonit, nickeline, pentlandite, proustite, pyrargyrite, pyrite.
- Halides. Breit, hilit, creedite, fluorite, cryolite, protopic.
- Oxides, hydroxides. Agate, alexandrite, amethyst, anatase, aventurine, dendrite, rock crystal, blue quartz, brookite, chalcedony, chrysoprase, citrine, Jasper, cat's eye, opal, sapphire, carnelian, tiger's eye.
- Carbonates, nitrates. Ankerite, aragonite, azurite, dolomite, gaspeite, malachite, static, Velogenic.
- The borates. Boratsit, howlite, Indesit, peynit, ulexite, Sinhala.
- Sulphates, chromates, molybdates, tungstates. The anglesite, barite, Celestine, gypsum, linarite, scheelite, wulfenite.
- Phosphate, arsenate, Vanadate. Adamite, Apatite, durangite, turquoise, lazulite, monazite.
- Silicates. Achroite, albite, charoite, moonstone, lapis lazuli, jade, sapphirine, emerald, talc, Topaz, zircon.
- Organic matter. Umbreit, amber, Melita, wavelet.