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Roger Weller, geology instructor

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aquamarine
by Ann Baxter
Physical Geology
Fall 2014
                  

The Magical Gemstone ~ Aquamarine

Aquamarine occurs in ocean-like shades of greenish-blue, blue-green, and blue.

It is the birthstone for the month of March.

 

 

 

 

 

 

Group:

The aquamarine stone is part of the beryl group. Beryl is an accessory mineral in granites. It can be found in granite pegmatites and cavities. Beryl is usually clear, but the presence of iron gives it the bluish tint to reveal the gemstone we all know as aquamarine.

 

 

 

 

 

History:

            In the 19th century the preferred color of the aquamarine stone was sea green. The sea green color that was all the rage back then came from an urban legend. Back then, many believed the stone to have been a treasure from the treasure chests of mermaids, who lived deep in the ocean. Sailors used to bring this gem along with them on long voyages as a good luck charm to them and their crew aboard the ship. In its' lighter shades of blue, it cooled and relaxed the body. It is said to bring serenity and peace to those who keep it near. Some believe that the aquamarine is the stone of the magic genie, who will grant wishes and desires to those who possess it.  The name aquamarine derives from the Latin words “aqua”, meaning water, and “mare”, meaning sea.

 

 

 

 

 

 

One of the biggest aquamarine stones found was in 1910 in Brazil. The stone weighed out to two-hundred and forty three pounds. It was fifteen point fifteen inches in diameter and it was cut into little gems of a total weight of one-hundred thousand carats.

Identifying Aquamarine:

            The gemstone can be identified by is sea-blue colors and vitreous luster. They have excellent transparency and clarity. The intense color and the quality of the cut in the stone, help to identify it. It is colored by trace amounts of iron. Its six-sided crystalline structure, help to sort it out from other blue-colored gems.

Types:

Cat’s Eye Aquamarine:

This is a greenish-blue aquamarine that has a Chatoyancy. This rare occurrence is when light shines on the stone  and creates a reflection that looks like a cat’s eye. When the stone is turned slowly, a long slit will appear across the stone.

 

 

 

 

 

Star Aquamarine:

            This is caused by reflections off tube-like silk aligned in two or three directions causing four or six ray stars.
 

 

 

 

 

 

Today’s quality:

Today the stone is known for its blue appearance. A top of the line gemstone should be clear with little to no inclusions. Most aquamarine stones are heated to remove any yellow tinge, thus producing a more blue stone. The gemstone is not very high on the market because it is so common around the world. Over the years the exquisiteness of the aquamarine gemstone has decreased.

 

 

 

 

 

 

 

Where it originates from:

The best quality aquamarine gemstones come from Brazil. Other places that aquamarine is found, includes Russia, Pakistan, Afghanistan, India, and Nigeria. A dark blue variety comes from Madagascar.

Commonalities:

            Kyanite is a mineral often mistaken for aquamarine due to its blue pigmentation. Although this mineral is mistaken for aquamarine, the two are not in the same family of stones.











 

 

 

 

 

 

 
 

            The emerald is in the same family as the aquamarine. They are both beryllium aluminum silicates. Emerald’s color comes from trace amounts of chromium and vanadium, and aquamarine’s color comes from the result of iron impurities with beryl crystal. Both gemstones have the same gravity and refractive index. Aquamarine has remarkable transparency and clarity, while emerald is quite hazy and contains inclusions.

 

 

 

 

 

 

AQUAMARINE

Chemical composition

Be₃Al₂Si₆O₁₈

Color

Blue

Refractive index

1.57-1.59

Relative density

2.68-2.80

Hardness

7.5-8

Crystal group

Hexagonal

Cleavage

One direction, poor

Fracture

Conchodial

Tenacity

Brittle

Luster

Vitreous

Transparency

Transparent to translucent

Dispersion

Low, .014

Birefringence

Low, .004-.007

Pleochroism

Weak

 

Works Cited:

Hall, Cally. Gemstones. New York City, Dorling Kindersley, 1994. Page 76.

Oldershaw, Cally. Gems of the World. Buffalo, Firefly Books, 2008. Pages 156-157.

http://geology.com/minerals/photos/kyanite-cabochons.jpg

http://www.thegemtrader.com/Mar11SAquaI.gif

http://www.gemselect.com/photos/cats-eye-aquamarine/cats-eye-aquamarine-gem-333925a.jpg

http://www.traxnyc.com/gallery/Baguette-Cut-Emerald-and-Round-Diamond-Gemstone-Ring-In-18K-White-Gold-Gemstone-Diamond-Rings-1.jpg

http://sabrinasilver.com/sabrinasilver/ShopCart/impl/images/product_images/RDIA30312.jpg

http://media-cache-ec0.pinimg.com/236x/e6/48/80/e648804f316dad576cf484e3fc9e7882.jpg

http://i1.ytimg.com/vi/nBbcsj_eDks/maxresdefault.jpg

http://royalexhibitions.files.wordpress.com/2010/05/76018.jpg

http://ak1.ostkcdn.com/images/products/5618221/Miadora-Sterling-Silver-Aquamarine-and-Diamond-Accent-Ring-P13377105.jpg

http://www.grandgemstones.com/images/8008/big/800810869a.jpg

http://www.list-of-birthstones.com/Pictures%20of%20Birthstones/Aquamarine%20birthstones%203.jpg

http://c940564.r64.cf2.rackcdn.com/coloursoflight/1359720887821785/f75c55e9361c959d92da4fbfa36518a9.jpg

http://1.bp.blogspot.com/-HDIStIQkmqs/UzJW_jo4h1I/AAAAAAAADds/6YqtC6TXLLU/s1600/14004-Aquamarine-lt-blue-crystals_456.png.png

http://www.ringswithlove.com/wp-content/uploads/2013/03/aquamarine-gemstones-March-birthstone-jewelry.jpg

http://www.dandennis.com/aquamarine1.htm

http://www.gemselect.com/gem-info/aquamarine/aquamarine-info.php