See Also

Emerald

Emerald is a variety of the mineral Mineral

Minerals are natural compounds formed through geological [i] processes. ... 

 beryl, colored green by trace amounts of chromium Chromium

Chromium is a chemical element [i] in the periodic table [i] that has the symbol Cr and atomic number [i] ... 

 and sometimes iron Iron

Iron is a chemical element [i] with the symbol Fe and atomic number [i] 26. ... 

. It is highly prized as a gemstone Gemstone

A gemstone is a mineral [i], rock [i] , or petrified [i] material that when cut or f ... 

 and by weight is the most valuable gemstone in the world, although it is often made less so by inclusions, which all emeralds have to some degree. Beryl has a hardness Hardness

In materials science [i], hardness is the characteristic of a solid [i] material expressing its resistan ... 

 of 7.5 on the 10 point Mohs scale of hardness. However, this Mohs rating can decrease, depending on the number and severity of inclusions in a particular stone. Most emeralds are oiled as part of the post lapidary process.

Discussions

  Discussion Features

   Ask a question about 'Emerald'

   Start a new discussion about 'Emerald'

   Answer questions about 'Emerald'

   'Emerald' discussion forum


Encyclopedia

Emerald


Emerald with inclusions
General
CategoryMineral Mineral

Minerals are natural compounds formed through geological [i] processes. ... 

Chemical formula Chemical formula

A chemical formula is a concise way of expressing information about the atom [i]s that constitute a par ... 

Beryllium Beryllium

Beryllium is the chemical element [i] in the periodic table [i] that has the symbol Be and atomic number [i] ... 

 aluminium Aluminium

Aluminium or aluminum is the chemical element in the periodic table that has the symbol Al ... 

 silicate with chromium Chromium

Chromium is a chemical element [i] in the periodic table [i] that has the symbol Cr and atomic number [i] ... 

, Be3Al26Cr
Identification
Color Green
Crystal habit Crystal habit

In mineralogy [i], shape and size give rise to descriptive terms applied to the typical appearance, or habi... 

 
Hexagonal Crystals
Crystal system Crystal structure

In mineralogy [i] and crystallography [i], a crystal structure is a unique arrangement of atoms in a crystal [i] ... 

 
Hexagonal
Cleavage Poor Basal Cleavage
Fracture Conchoidal
Mohs Scale hardness 7.5 - 8.0
Lustre Vitreous
Refractive index 1.576 - 1.582
Pleochroism Distinct, Blue-Green/Yellow-Green
Streak Mineral

Minerals are natural compounds formed through geological [i] processes. ... 

White
Specific gravity 2.70 - 2.78

Emerald is a variety of the mineral Mineral

Minerals are natural compounds formed through geological [i] processes. ... 

 beryl, colored green by trace amounts of chromium Chromium

Chromium is a chemical element [i] in the periodic table [i] that has the symbol Cr and atomic number [i] ... 

 and sometimes iron Iron

Iron is a chemical element [i] with the symbol Fe and atomic number [i] 26. ... 

. It is highly prized as a gemstone Gemstone

A gemstone is a mineral [i], rock [i] , or petrified [i] material that when cut or f ... 

 and by weight is the most valuable gemstone in the world, although it is often made less so by inclusions, which all emeralds have to some degree. Beryl has a hardness Hardness

In materials science [i], hardness is the characteristic of a solid [i] material expressing its resistan ... 

 of 7.5 on the 10 point Mohs scale of hardness. However, this Mohs rating can decrease, depending on the number and severity of inclusions in a particular stone.

Most emeralds are oiled as part of the post lapidary process. The amount of oil entering an emerald microfissure is roughly equivalent to the size of a period in print.

Emeralds come in many shades of green and bluish green. There is a wide spectrum of clarity, along with various numbers of inclusions. Most emeralds are highly included, so it is quite rare to find an emerald with only minor inclusions.

A rare type of emerald known as a trapiche emerald is occasionally found in the mines of Colombia Colombia

The Republic of Colombia , is the northwesternmost country of South America [i]. ... 

. A trapiche emerald exhibits a "star" pattern; it has raylike spokes of dark carbon impurities that give the emerald a six-pointed radial pattern. It is named for the trapiche, a grinding wheel used to process sugarcane Sugarcane

[i]
... 

 in the region.

Synthetic emerald


Emerald is a rare and valuable gemstone and, as such, it has provided the incentive for developing synthetic emeralds. Both hydrothermal and flux-growth synthetics have been produced and a method has been developed for producing an emerald overgrowth on colorless beryl. The first commercially successful emerald synthesis process was that of Carroll C. Chatam. Because Chatam's emeralds do not have any water and contain traces of vanadate, molybdenum and vanadium, a lithium vanadate flux process is probably involved. The other large producer of flux emeralds is Pierre Gilson Sr. which has been on the market since 1964. Gilson's emeralds are usually grown on natural colorless beryl seeds which become coated on both sides. Growth occurs at the rate of 1 mm per month and a typical seven-month growth run produces emeralds crystals of 7 mm of thickness .

Hydrothermal synthetic emeralds have been attributed to IG-Farben, Nacken, Chatam and others but the first satisfactory commercial product was that of Johann Lechleitner of Inbruck, Austria, which appeared on the market on the 1960's. These stones were initially sold under the names "Emerita" and "Symeralds" and they were grew as a thin layer of emerald on top of natural colorless beryl stones. Although not much is known about the original process, it is assumed that Leichleitner emeralds were grown on acid conditions. Later, from 1965 to 1970, the Linde Division of Union Carbide produced completely synthetic emeralds by hydrothermal synthesis. According to their patents acidic conditions are essential to prevent the chromium from precipitating. Also, it is important that the silicon containing nutrient be kept away from the other ingredients in order to prevent nucleation and confine growth to the seed crystals. Growth occurs by a diffusion-reaction process, assisted by convection. Typical growth conditions include pressures of 700-1400 bars at temperatures of 500oC to 600oC with a temperature gradient of 10 to 25 C. Growth rates as fast as 1/3 mm per day can be attained.

Flux-grown synthetic emeralds fluoresce Fluorescence

Fluorescence is a luminescence [i] that is mostly found as an optical phenomenon [i] in cold bodies, in ... 

 a dull red with long wave Longwave

The Longwave radio [i] broadcasting band are those frequencies between 153 - 279 kHz [i], which correspo ... 

 ultraviolet Ultraviolet

Ultraviolet light is electromagnetic radiation [i] with a wavelength [i] shorter than that of visible l ... 

 light, due to an indicator added during the process of synthesizing the emerald, whereas natural specimens do not.

Synthetic emeralds are often referred to as "created", as their chemical and gemological composition is exactly same as its natural counterparts. The Federal Trade Commission Federal Trade Commission

The Federal Trade Commission is an independent agency of the United States government [i] ... 

  has very strict regulations as to what can and what can not be called "synthetic" stone. The FTC says: "...[created stone must have] essentially the same optical, physical, and chemical properties as the stone named."

Furthermore, all natural emeralds, with the exception of the red Bixbite Bixbite

Bixbite is a red variety of beryl [i], Be3(Al,Mn)2Si6O18. ... 

 beryls from Utah which are anhydrous, have water inclusions, as emerald is of hydrothermal origin. Flux synthetic emeralds have no water, an integral part of any natural beryl . Hydrothermally-grown emeralds, however, contain water molecules.

Wispy veil-like inclusions are common in flux-grown synthetic emeralds.

.

Cultural and historical/mythical usage


Emerald is regarded as the traditional birthstone Birthstone

Sorry, no overview for this topic 

 for May, as well as the traditional gemstone for the astrological signs of Cancer and Taurus. According to legend, the emerald has the power to protect the chastity Chastity

Chastity, in many religious [i] and cultural [i] contexts, is a virtue [i] concerning t ... 

 of the wearer and to ward off evil spirits. Furthermore, it was believed to cure epilepsy Epilepsy

Epilepsy is a common chronic [i] neurological [i] condition that is characterized by ... 

 and dysentery, and to aid weak eyesight. The Emerald is also a symbol of Pride.

According to Rebbenu Bachya Bahya ben Asher

Bahya ben Asher or Bahya ben Asher ben Halawa also known as the Rabbeinu Behaye, born about ... 

, the Hebrew Hebrew language

Hebrew is a Semitic language [i] of the Afro-Asiatic language family [i] ... 

 word "Nofech" in Exodus 28:18 means "Emerald", and was the stone on the Ephod representing the tribe of Judah Tribe of Judah

The Tribe of Judah is one of the Hebrew tribe [i]s, founded by Judah [i], son of Jacob [i].
... 

. According to other commentaries, "Nofech" means "garnet Garnet

The garnet group of mineral [i]s show crystal [i]s with a habit of rhombic dodecahedron [i]s and trapezohedron [i] ... 

", and another stone, the "Bareqet", representing the tribe of Levi, is thought to be the emerald.

In some cultures, the emerald is the traditional gift for the 55th wedding anniversary. It is also used as a 20th and 35th wedding anniversary stone.

Famous emeralds


  • Gachala Emerald Gachala Emerald

    The Gachala Emerald, an uncut 5-cm [i] emerald [i] crystal weighing 858 carats [i]. ... 

  • Chalk Emerald
  • Duke of Devonshire Emerald
  • Mackay Emerald

References

  • Cooper, J.C. . Brewer's Myth and Legend. New York: Cassell Publishers Ltd. ISBN 0-304-34084-7.
  • Sinkankas, John . Emerald & Other Beryls. Geoscience Press. ISBN 0-8019-7114-4
  • Hurlbut, Cornelius S.; Klein, Cornelis . Manual of Mineralogy . New York: John Wiley and Sons. ISBN 0-471-80580-7
  • Weinstein, Michael . The World of Jewel Stones. Sheriden House.