Gemstones

A gemstone or gem (also called a precious or semi-precious stone, or jewel) is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments. However certain rocks, (such as lapis lazuli) and organic materials (such as amber or jet) are not minerals, but are still used for jewelry, and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their lustre  r other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone.
The traditional classification in the West, which goes back to the Ancient Greeks, begins with a distinction between precious and semi-precious stones; similar distinctions are made in other cultures. In modern usage the precious stones are diamond, ruby, sapphire and emerald, with all other gemstones being semi-precious. This distinction reflects the rarity of the respective stones in ancient times, as well as their quality: all are translucent with fine color in their purest forms, except for the colorless diamond, and very hard, with hardnesses of 8–10 on the Mohs scale. Other stones are classified by their color, translucency and hardness. The traditional distinction does not necessarily reflect modern values, for example, while garnets are relatively inexpensive, a green garnet calledTsavorite, can be far more valuable than a mid-quality emerald. Another unscientific term for semi-precious gemstones used in art history and archaeology is hardstone. Use of the terms 'precious' and 'semi-precious' in a commercial context is, arguably, misleading in that it deceptively implies certain stones are intrinsically more valuable than others, which is not the case.
In modern times gemstones are identified by gemologists, who describe gems and their characteristics using technical terminology specific to the field of gemology. The first characteristic a gemologist uses to identify a gemstone is its chemical composition. For example, diamonds are made of carbon (C) and rubies of aluminium oxide (Al2O3). Next, many gems are crystals which are classified by their crystal system such as cubic or trigonal or monoclinic. Another term used is habit, the form the gem is usually found in. For example diamonds, which have a cubic crystal system, are often found as octahedrons.
Gemstones are classified into different groups, species, and varieties. For example, ruby is the red variety of the species corundum, while any other color of corundum is considered sapphire. Emerald (green), aquamarine (blue), red beryl (red), goshenite (colorless), heliodor (yellow), and morganite (pink) are all varieties of the mineral species beryl.
Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture, and luster. They may exhibit pleochroism or double refraction. They may haveluminescence and a distinctive absorption spectrum.
Material or flaws within a stone may be present as inclusions.
Gemstones may also be classified in terms of their "water". This is a recognized grading of the gem's luster and/or transparency and/or "brilliance". Very transparent gems are considered "first water", while "second" or "third water" gems are those of a lesser transparency.

(Turquoise)

It is a blue-green opaque mineral. The French called it turquoise and Venetians turchesa meaning "Turkey" because Europeans traders medieval bought turquoise in Turkish bazaars, where he had arrived from Persia. It is rare and prized. All ancient cultures have used for etching,for talisman jewelry. The death mask in the tomb of Pharaoh Tutankhamun in Egypt was from turquoise, like rings found in his grave. The Aztecs used turquoise and other gemstones with gold to create a kind of mosaic, decorating knives, shields, masks, KLn To date the traditional jewelry of the American Indians are based turquoise. . The peoples of Mesopotamia, the people in the valley of the Indus, and the Chinese also knew and used the turquoise. In ancient Greece was known as kallaitis or kallais stone. Pliny we find the name callaina or "good stone".
   The turquoise is a porous mineral, which has high stability. Due to the great demand have been many imitation turquoise. The most common is painted chaouliti. Upon exposure to light, and on contact with ambient air, spray, etc., tends to change its color.To remain stable, often covering the surface with a special varnish. As to the creation of the turquoise is a secondary mineral, which means created by the interaction preexisting minerals.

 (Coral)

Among the most impressive semiprecious stones is the coral (coral). Corals are underwater formations that resemble tree branches. Their branches carefully picked by hand from the bottom of the oceans, cleaned and polished before they come in the form that we find in our jewelry.The color of coral can be white, pink, blue, black, but the most popular and timeless are red coral.
Corals are a "female" semiprecious stone. Worn in many parts of the world as jewelry for centuries. Jewelry found coral from prehistory. The ancient Egyptians dedicated to Isis,Romans Venus. In ancient Greece corals called "gorgonides" because the ancient tradition said that corals were formed from the blood of a mermaid. Pliny says that the Indian seers believe how someone wearing coral, is a powerful deterrent to many risks,and how they use them in magical rites. In Buddhist scriptures cited as one of the seven treasures and is considered a very powerful protector from evil spirits. The ancients believed that the coral can stop the bleeding and to protect people from extreme weather events.Generally the coral is considered a semiprecious stone that brings happiness and luck.
The word coral probably has Greek etymology: kori- alos, ie, the daughter of the sea.

 ( Jade ).

The Jade in terms of transparency is translucent to opaque. The colors that we can meet spanning all shades of green and reach yellow, brown, black etc.
The name "Jade" was derived from the Spanish conquistadors and so named because of the use of this stone from the Mexicans. Since ancient times,the Maya and Aztecs used it for relieving the kidney. In Spanish called "piedra de ijada" meaning "stone sides". Eventually the Spanish phrase evolved into "Jade." Since the beginning of the Roman civilization, jade was used by the peoples of the Mediterranean for the treatment of kidney disease, such as nephritis,and so called "nephriticus lapis" for the "stone of nephrite." Ultimately then reduced to "nephrite" and is often used as an alternative name Jade.

(Tiger Eye)

One of the most special and charming stone family of quartz, with color ranging from light to dark brown with golden highlights. Is silica composition and displays bright yellow and brown parallel fibers. The presence of iron oxide gives the stone its color yellow and gold.The interesting feature of this stone is the bar of iridescence that looks like moving silky sheen. These lines are alternately gold and brown color and the texture is fibrous krokkidolithos.The very characteristic optical phenomenon is known by the French word chatoyancy you say in Greek the "cat's eye".
Roman soldiers wore this semi-precious stone, because they believed that it was the "eye that sees everything."

( Amethyst )

The name is because the ancient Greeks believed that wearing jewelry with amethyst or drinking wine in cup of amethyst, softened the effects of intoxication. In Greek mythology, the amethyst occurs when the drunken god Dionysus attacks in a bad mood to a virgin daughter is named the "Amethyst".The girl does not respond, and to save seeks the help of the gods. Goddess was one that responded to her prayers, namely Artemis to save the girl, transforms into a colorless stone. Humiliated and angry Dionysus, pours wine over the crystals of stone taking the beautiful purple color.In a variant of the myth stone painted not by the wine but the tears of repentant Dionysus.
In ancient China believed that if someone was holding him during a trial and he was right, would win the case.
Chemical amethyst is quartz, SiO2.Is strikingly beautiful material and has the potential to be used (and certainly used) in jewelery. Nevertheless the price remains low because of the large quantities extracted. But not always. The most sought-after quality amethyst, the so-called "Deep Russian", it costs at least $ 50,000 a carat.

( Pink Quartz )

You can meet him called pink quartz and pink quartz. The pink color in rose quartz generated from impurities titanium, iron, and magnesium present in the mass. Larger quantities pink quartz unsatisfactory clarity and color to be used in jewelery.It has been used both as decorative and religious objects from the beginning of history. In ancient times, except for jewelry, it used to make cups and utensils intended for public figures.Also was the material used to make magical crystal balls! Elaborately carved statues in the style of Chinese art is widespread. Nowadays spheres and pyramids of rose quartz are preferred as a beautiful and decorative alternative.

 ( Moonstone )

The Moonstone or otherwise Selinolithos is a transparent variety of the group of potassium feldspar with a variable, undulating pearl luster because of blue iridescence of perceived light when we turn to stone under the light and looks as if it moves one iridescent line on the surface of .The name comes because it resembles the glow of the moon. In the past it was said that this could see the crescent and moon phases. Also believed that the stone had greater forces when he was a full moon.

 ( Green Quartz or Prasiolite)

The green quartz or praseolithos is a form of quartz rare in nature. The name comes from the words "leeks" and "stone", suggesting the green color.
He sold today as green quartz is actually amethyst that has undergone heat treatment (usually amethyst turns into citrine,But some varieties will become green quartz when heated at 500 ° C).