The name is of ancient origin. The Latin Smaragdus appears, infact, to have referred to the stone we call emerald, which is now considered as a distinct species. It is basically the green variety of beryl, although all gem-quality green beryls are called emeralds: yellow-green stones are called heliodors; soft-green or even pale green specimens (their color due to iron, not chromium, as in emerald) are called aquamarines.



Appearance:
The typical is a beautiful; distinguish hue known, infact, as emerald green is due to traces of chromium in the crystal structure. But emerald can be light or dark green, bright green or leaf green. The vitreous luster is not outstanding, is the strongest in the medium-light stones with few inclusions. All emeralds contain inclusions, although in the best quality stones, these are very faint and not visible to the naked eye. They show up under a 10x, 20x, or 40x lens. The most common shape for gems is the step or trap cut, which also known as the emerald cut. They are occasionally given a mixed, oval, while antique stones are found with hexagonal, step cuts cabochon cuts, or pear shape with the whole in them, often use as pendants.



Distinct features:
The typical emerald colored is virtually unmistakable. It is only equaled by some very rare specimens of jadeite jade, which however is less transparent has different physical properties. To the initiated, the inclusions in emerald can be highly distinctive: a bubble of gas in a liquid (like a spirit level), within spindle-shaped or, more rarely, truncated prismatic cavities; birefringence, circular plates of mica; multifaceted pyrite crystals or calcite rhombohedra. However, in microscope is almost always needed to recognize them. Although not the typical emerald color, come green tourmalines may look similar, but they can be distinguish either by their marked pleochroism, or by the fact that tourmaline which are given a emerald display alternating, longitudinal lines of lighter or darker color, when viewed through the table facets. Olivine may also be verdant green color vaguely similar to that of some a typical emerald; but the powerful birefringence of olivine is detectable with the simple lance, a double image of opposite facet edges is being clearly visible in certain directions through the table facet. In any case, the density of either tourmaline or olive immediately distinguishes the stone from emerald.



Occurrence:
The biggest and most beautiful emeralds come from the famous Chivor and Muzo mines of Columbia. Much smaller quantities of emeralds, mostly of medium-light color, come from Brazil, and small, very intensely color stones characterized by numerous minute inclusions of molybdenite with a metallic appearance, are found in the Transvaal. In the last few decades, increasing quantities of emeralds have been found in a series of small deposit in east Africa- principally in Zimbabwe, Zambia, and Tanzania. These are quite a strong color, sometimes with a bluish-green tinge; and they often contain mica plates and, sometimes, thin crystal needles. The most famous of these emeralds are the ones from Sandwana in Zimbabwe, which are valued for their color. Emeralds with similar characteristics also come from the mountains of India and Pakistan, as well as the Soviet Union (Urals), and formally Australia.



Value:
Stones of fine color, weighing more than two carats are among the most highly value gemstones, and their price may equal or exceeds that may of diamonds. Less idly color varieties- too dark or too pale-are worth quite lot less; and if they are slightly turbid as well, the value is reduced even further.



Simulants and Synthetics:
The Romans are known to have imitated emerald with skillfully worked green glass. Glass was also used in later centuries, extraneous particles sometimes being in incorporated to simulate inclusions.

Doublets have also been used as imitations, with lower portion of green glass and a top portion of garnet, or triplets, with a layer of color cement sandwiched between two layers of colorless beryl, synthetic spinal, or quartz, synthetic emeralds have likewise been widely produced over the last few decades. Generally of good color, these are mainly distinguished from the natural variety by their inclusions and other growth features. There are a lot of these synthetic stones about, but their cost is quite high, so that the market for them is saturated.