Archive:Aquamarine

2007-12-16T23:30:32Z

70.228.69.2: /* See also */

{{otheruses1|the mineral}}
{{Infobox mineral
| name = Aquamarine
| category = [[beryl]] variety
| boxwidth =
| boxbgcolor =
| image = Aquamarin cut.jpg
| imagesize = 250px
| caption = Aquamarine
| formula = Be3Al2Si6O18<ref name="GRG"/>
| molweight =
| color = transparent (or can be translucent if included), greenish blue to blue green, typically light in tone<ref name="GRG">[[Gemological Institute of America]], ''GIA Gem Reference Guide'' 1995, ISBN:0-87311-019-6</ref>
| habit =
| system = [[hexagonal]]<ref name="GRG"/>
| twinning =
| cleavage = very difficult in one direction, almost never seen<ref name="GRG"/>
| fracture = [[conchoidal]]<ref name="GRG"/>
| mohs = 7.5 - 8<ref name="GRG"/>
| luster = [[vitreous]] to resinous<ref name="GRG"/>
| polish = [[vitreous]] <ref name="GRG"/>
| refractive = 1.577 - 1.583 (+/- .017)<ref name="GRG"/>
| opticalprop = Double refractive, uniaxial negative<ref name="GRG"/>
| birefringence = .005 - .009<ref name="GRG"/>
| dispersion = .014<ref name="GRG"/>
| pleochroism = weak to moderate, blue and greenish blue; or different tones of blue with lighter tones associated with the optic axis direction <ref name="GRG"/>
| fluorescence= inert<ref name="GRG"/>
| absorption = indistinct lines at 537 and 456nm. Depending on the depth of color, there is a strong line at 427nm.<ref name="GRG"/>
| streak =
| gravity = 2.72 (+.18, -.05)<ref name="GRG"/>
| density =
| melt =
| fusibility =
| diagnostic =
| solubility =
| diaphaneity =
| other =
}}
[[Image:Beryl09.jpg|thumb|left|250px|Three Beryl Crystals - Aquamarine rough crystal in the center]]
'''Aquamarine''' (Lat. ''aqua marinā'', "water of the sea") is a [[gemstone]]-quality transparent variety of [[beryl]], having a delicate blue or [[turquoise]] color, suggestive of the tint of [[seawater]]. It's closely related to the gem [[emerald]]. Colors vary and yellow beryl ([[heliodor]]), rose pink beryl ([[morganite]]), and white beryl ([[goshenite]]) are known.

==Composition==
Aquamarine is a beryl with a [[Hexagonal (crystal system)|hexagonal]] [[crystal structure]] and a [[chemical formula]] of Be3Al2Si6O18, a [[beryllium]] [[aluminium]] [[Silicate minerals|silicate mineral]]. It has a [[specific gravity]] of 2.68 to 2.74 and a [[Mohs hardness]] of from 7.5 to 8. Aquamarine typically is on the low end of the specific gravity range, normally at less than 2.7. The pink variety exhibits a high specific gravity of around 2.8. [[Refractive index|Refractive indices]] range around 1.57 to 1.58.

==Locations of deposits==
It occurs at most localities which yield ordinary beryl, some of the finest coming from [[Russia]]. The gem-gravel [[Placer mining|placer]] deposits of [[Sri Lanka]] contain aquamarine. Clear yellow beryl, such as occurs in [[Brazil]], is sometimes called aquamarine chrysolite. When [[corundum]] presents the bluish tint of typical aquamarine, it is often termed Oriental aquamarine.

In the [[United States]], aquamarines can be found at the summit of [[Mount Antero|Mt. Antero]] in the [[Sawatch Range]] in central [[Colorado]]. In [[Brazil]], there are mines in the states of [[Minas Gerais]], [[Espírito Santo]] and [[Bahia]]. Zambia also produces nice aquamarine as well as Madagascar, Malawi, Tanzania and Kenya. Much of today's aquamarine is heated to give it a better color blue. The deeper the blue color, the more valuable the gem is considered.

The biggest aquamarine ever mined was found at the city of Marambaia, Minas Gerais, Brazil, in 1910. It weighed over 110 kg, and its dimensions were 48.5 cm long and 42 cm in diameter.

Aquamarine is the [[List of U.S. state minerals, rocks, stones and gemstones|official state gem]] of Colorado.

==Culture and historical/mythical usage==
*Aquamarine (along with Bloodstone) is the [[birthstone]] associated with March. It is also the gemstone for the 19th Anniversary.
*People in the [[Middle Ages]] thought that aquamarine could magically overcome the effects of [[poison]].
*Ancient sailors traveled with aquamarine crystals, believing that it would ensure a safe passage, and guarantee a safe return; they often slept with the stones under their pillow to ensure sound sleep. They believed the siren’s ([[mermaid]]) fish-like lower body was made of aquamarine.

== See also ==
{{commonscat|Aquamarine}}
* [[List of minerals]]
aquamarin is blue!

== References ==
<references/>
* Weinstein, Michael, 1958, ''The World of Jewel Stones'' Sheriden House, New York, pp 104-107
* Diamond Bug. [http://diamondbug.blogspot.com/2006/03/flawless-aquamarine-march-birthstone.html "Flawless Aquamarine: March Birthstone"]. Retrieved March 16, 2006.
*http://www.gemstone.org/gem-by-gem/english/aquamarine.html
*http://mineral.galleries.com/minerals/gemstone/aquamari/aquamari.htm
*http://www.mindat.org/min-289.html

{{Jewellery Materials}}
{{Gems & Crystals}}
[[Category:Silicate minerals]]
[[Category:Gemstones]]

[[bg:Аквамарин]]
[[da:Akvamarin]]
[[de:Aquamarin]]
[[et:Akvamariin]]
[[es:Aguamarina]]
[[fr:Aigue-marine]]
[[gl:Augamariña]]
[[he:אקוומרין]]
[[lv:Akvamarīns]]
[[lt:Akvamarinas]]
[[nl:Aquamarijn]]
[[ja:アクアマリン]]
[[no:Akvamarin]]
[[pl:Akwamaryn]]
[[pt:Água-marinha]]
[[ro:Acvamarin]]
[[ru:Аквамарин]]
[[sl:Akvamarin (kamen)]]
[[sr:Аквамарин]]
[[fi:Akvamariini]]
[[sv:Akvamarin]]
[[vi:Ngọc berin]]
[[tr:Akuamarin]]
[[uk:Аквамарин]]

Wolf pack

2006-11-09T17:08:57Z

70.228.29.126:

:''This article describes the system of submarine warfare. For other meanings, see [[wolfpack]].''

[[I LOVE YOU, ACORNS ROCK!]] i want pizza and soda..in my grill.

The term '''wolf pack''' refers to the mass-attack tactics against [[convoy]]s used by [[U-boat]]s of the [[Kriegsmarine]] during the [[Second Battle of the Atlantic|Battle of the Atlantic]] and [[submarine]]s of the [[United States Navy]] against [[Japan]]ese shipping in the [[Pacific Ocean]] in [[World War II]].

[[Karl Dönitz]] used the term ''Rudel'' to describe his strategy of submarine warfare – ''Rudel'' can be translated as "pack" of animals, but it also translates as herd, pride, or swarm, depending on the type of animal associated with the word, so this has become known in [[English language|English]] as "wolf pack" (''Wolfsrudel''), a more accurate metaphoric, but not literal, translation.

U-boat movements were controlled by the ''[[Befehlshaber der Unterseeboote]]'' much more closely than American submarines, which were given tremendous independence once on patrol. Accordingly, U-boats usually patrolled separately, often strung out in co-ordinated lines across likely convoy routes, only being ordered to congregate after one located a convoy and alerted BdU, so a ''Rudel'' consisted of as many [[U-boat]]s as could reach the scene of the attack. American wolf packs, usually comprised three boats that patrolled in close company, organized before they left port under the command of the senior captain of the three. [[Charles Momsen|"Swede" Momsen]] devised the tactics and led the first American wolf pack to sea in October [[1943]].

Wolf packs fell out of use during the [[Cold War]]; modern submarines being so much more maneuverable and destructive than those of [[World War II]] that there is no need for them to hunt in packs. Instead, the [[United States Navy]] deploys its attack submarines on individual patrols, with the exception of one or (rarely) two attack submarines in each carrier group. American ballistic missile submarines have always operated alone. (Soviet ballistic missile submarines operated in well-protected [[bastion (submarine)|bastion]]s.) However, with the opening shots of the [[2003 invasion of Iraq]] in March 2003, the term "wolf pack" was brought back into use to describe the fleet of American and British [[nuclear submarine]]s which operated together in the [[Red Sea]] to fire [[BGM-109 Tomahawk|tomahawk missiles]] at [[Iraq]]. [[USS Providence (SSN-719)|USS ''Providence'']] was the first boat to fire its entire load of missiles and earn the nickname "Big Dog of the Red Sea Wolf Pack."

== References ==
* Karl Dönitz, ''Memoirs: Ten Years and Twenty Days'' (New York: World Publishing Company, 1958)

* Peter Maas, ''The Terrible Hours: The Man Behind the Greatest Submarine Rescue in History'' (HarperCollins New York, 1999)

* E. B. Potter and Chester W. Nimitz, eds; ''Sea Power: A Naval History'' (Englewood Cliffs, N.J.: Prentice-Hall, 1960)

[[Category:Naval warfare]]

[[de:Wolfsrudeltaktik]]
[[ja:群狼作戦]]
[[sr:Вучји чопор]]

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Archive:Aquamarine

Wolf pack