Aquamarine (gem)

Aquamarine
Aquamarine on muscovite
General
Category	Silicate minerals, beryl variety
Formula (repeating unit)	Be3Al2Si6O18
Identification
Color	Pale blue to light green
Fracture	Conchoidal
Mohs scale hardness	7.5–8
Streak	White[1]
Diaphaneity	Transparent to translucent
Specific gravity	2.65–2.85
Refractive index	1.57-1.59

Aquamarine is a pale-blue to light-green variety of the beryl family,^[2] with its name relating to water and sea.^[3] The color of aquamarine can be changed by heat, with a goal to enhance its physical appearance (though this practice is frowned upon by collectors and jewelers).^[4] It is the birth stone of March.^[5]

Aquamarine is a fairly common gemstone,^[6] rendering it more accessible for purchase, compared to other gems in the beryl family.^[7] Overall, its value is determined by weight, color,^[5] cut, and clarity.^[8]

It is transparent to translucent and possesses a hexagonal crystal system.^[9] Aquamarine mainly forms in granite pegmatites and hydrothermal veins,^[10] and it is a very lengthy process that can take millions of years to form.^[9]

Aquamarine occurs in many countries over the world, and is most commonly used for jewelry, decoration and its properties.^[11]

Aquamarine is mainly extracted through open-pit mining, however underground mining is also a possibility to access aquamarine reserves.^[12]

Aquamarine is a durable gemstone, but it is highly recommended to conserve it on its own to prevent damage/scratches.^[9]

Famous aquamarines include the Dom Pedro, the Roosevelt Aquamarine, the Hirsch Aquamarine, Queen Elizabeth's Tiara, Meghan Markle's ring, and the Schlumberger bow.^[13]

The name aquamarine comes from aqua (Latin for 'water'), and marine, deriving from marina (Latin for 'of the sea').^[3] The word aquamarine was first used in the year 1677.^[14][10]

The word aquamarine has been used as a modifier for other minerals like aquamarine tourmaline, aquamarine emerald, aquamarine chrysolite, aquamarine sapphire, or aquamarine topaz.^[15]

Aquamarine is blue with hues of green, caused by trace amounts of iron found within the crystal structure. It can vary from pale to vibrant and transparent to translucent. Better transparency in aquamarine gemstones means that light may go through the crystal with less interference. The hexagonal crystal system is where aquamarine crystallizes. It forms prismatic crystals with a hexagonal cross-section.^[9][16] These crystals can be microscopic to enormous in size and frequently feature faces with vertical striating. The lustre of aquamarine ranges from vitreous to resinous. It can have a glass-like brilliance and a sheen when cut and polished correctly.^[9]

Aquamarine has a chemical composition of Be₃Al₂Si₆O₁₈,^[5] also containing Fe²⁺.^[17] It belongs to the beryl family, being a beryllium aluminum silicate mineral. It is closely related to emerald, morganite, and heliodor. Aquamarine is chemically stable and resistant to most common chemicals and acids.^[9] It has a hardness of 7.5–8 on the Mohs scale.^[18][16] While aquamarine often contains no inclusions,^[19] it may possess them, with content such as mica, hematite, saltwater, biotite, rutile or pyrite.^[15] Its hardness on the Mohs scale of mineral hardness is rated as 7.5-8.^[16] This rating gives aquamarine the chance to be a very suitable gem for everyday wear.^[9]

Aquamarine mainly forms in granite pegmatites (coarse-grained igneous rock) and hydrothermal vents. The remaining liquid that is left behind after granitic magma crystallizes is what gives rise to pegmatites.^[10][9] The residual fluids, which are rich in volatile elements and minerals such as silicon, aluminum, and beryllium, concentrate when the magma cools and solidifies.^[9]

Aquamarine may also be formed by hydrothermal fluids, which are hot, mineral-rich solutions. These liquids contain dissolved minerals and metals as they move through fissures and cavities in the crust of the Earth. Fractures, faults, and veins are just a few of the geological environments that hydrothermal systems can be linked to.^[9]

Beryllium is a necessary component for the production of aquamarine, a type of beryl. Although beryllium is a relatively uncommon element in the crust of the Earth, it can be found in concentrated forms in some geological settings. These include beryllium-rich hydrothermal systems and granite pegmatites, which contain large amounts of beryllium-bearing minerals.^[9]

The dissolved elements start to precipitate out of the solution and form crystals as the hydrothermal fluids cool and come into contact with the right minerals and circumstances. Crystals of beryl, which include aquamarine, begin to form in pegmatite veins and host rock fissures or cavities. Aquamarine crystals grow over long periods, which enables them to take on their distinctive hexagonal prismatic shape.^[9]

This is a very long process that can take millions of years to form. The settings in which aquamarine forms can vary and may lead to variations in gem quality, size, and color.^[9]

The value of aquamarine is determined by its weight, color,^[5] cut, and clarity.^[8] Due to its relative abundance, aquamarine is comparatively less expensive than other gemstones within the beryl group, such as emerald or bixbite (red beryl), however it is typically more expensive than similarly colored gemstones such as blue topaz.^[19][6] Maxixe is a rarer variant of aquamarine, with its deep blue coloration,^[19] however, its color can fade due to sunlight.^[1] The color of maxixe is caused by NO₃.^[20] Dark-blue maxixe color can be produced in green, pink or yellow beryl by irradiating it with high-energy radiation (gamma rays, neutrons or even X-rays).^[21] Naturally occurring blue hued aquamarine specimens are more expensive than those that have undergone heat treatment to reduce yellow tones caused by ferric iron.^[6] Cut aquamarines that are over 25 carats will have a lower price per carat than smaller ones of the same quality.^[22] Overall, the quality and color will vary depending on the source of the gem.^[9]

Aquamarine is the birth stone for the month of March.^[5] It has historically been used a symbol for youth and happiness due to its color, which has also, along with its name, made Western culture connect it with the ocean.^[23][22] Ancient tales have claimed that aquamarine came from the treasure chests of mermaids; which led to sailors using this gemstone as a lucky charm to protect against shipwreck.^[24] Additionally, ancient Romans believed this stone had healing properties, due to the stone being almost invisible when submerged in water.^[7][10]

The Chinese used it to make seals, and showpiece dolls.^[25] The Japanese used it to make netsuke.^[26]

The Egyptians, Greeks, Hebrews, and Sumerians all believed that aquamarine stones were worn by the High Priest of the Second Temple. It was said that these stones were engraved to represent the six tribes of Israel. Greeks also engraved designs into aquamarine 2 thousand years ago and turned them into intaglios.^[27]

In our modern era, aquamarine is mainly used for jewelry, decoration and its properties.^[11] It can be cut and shaped into rings, earrings, necklaces, and bracelets.

Aquamarine became a state gem for Colorado in 1971.^[28]

Aquamarine can be found in countries like Afghanistan, China, Kenya, Pakistan, Russia, Mozambique, the United States,^[29] Brazil, Nigeria, Madagascar, Zambia, Tanzania, Sri Lanka,^[30] Malawi, India,^[5] Zimbabwe, Australia, Myanmar, and Namibia.^[31] The state of Minas Gerais is a major source for aquamarine.^[6]

Aquamarine can mostly be found in granite pegmatites.^[6] It can also be found in veins of metamorphic rocks that became mineralized by hydrothermal activity.^[5]

The largest known example is the Dom Pedro aquamarine found in Pedra Azul, Minas Gerais, Brazil, in the late 1980's. It weighs roughly 4.6 pounds, cut from a 100-pound aquamarine crystal, and measures 10,363 carats. It resides in the National Museum of Natural History in Washington.^[32]

The initial stages of the aquamarine mining process involve prospecting and exploration. Finding prospective locations or regions with aquamarine reserves is necessary. Geological mapping, remote sensing, mapping, remote sensing, sampling,^[12] and other methods are used by geologists and mining firms to locate potentially aquamarine-containing geological formations and structures. Preparation of the site is the next step, which includes removing any vegetation, leveling the land, and constructing the facilities - such as access roads and workspaces. It is possible to mine aquamarine using both open-pit and underground techniques. This will depend on the size of the operation, the features of the deposit, and environmental conditions.^[9]

The most popular technique for extracting aquamarine on a large scale is open-pit mining.^[12] In order to reveal the aquamarine-bearing ore, the soil, vegetation, and rock cover must be removed. The ore is extracted using trucks, bulldozers, and excavators, to remove the material.^[9]

Underground mining may occasionally be used to obtain aquamarine reserves. This process entails digging shafts and tunnels^[12] to reach the ore bodies or veins that contain gems. When the aquamarine deposit is deep or the surrounding rock is too hard for open-pit extraction, underground mining is used, even though it can be more difficult and expensive than open-pit mining.^[9]

After extraction, the ore containing aquamarine is delivered to a processing plant. To extract the aquamarine crystals from the surrounding rock and other minerals, the ore is crushed, processed, and occasionally cleaned. The aquamarine can be concentrated and purified using a variety of methods, such as magnetic separation, froth flotation, and gravity separation.^[9]

The aquamarine crystals are then sorted according to size, shape, color, and clarity following the initial processing. The gemstones are assessed and graded by gemologists and experts according to predetermined standards, such as the four C's (color, clarity, cut, and carat weight). Only the best aquamarine crystals are chosen to be used in jewelry made of gemstones.^[9]

Aquamarine is classified as a durable gem, however, it may still be damaged. In storage, it is advised to place it on its own, without the interruption of other gemstones to prevent scratches. Warm soapy water and a soft brush are the best ways to clean this gemstone, however, ultrasonic cleaners are relatively safe for aquamarine.^[9]

Although aquamarine is mainly used for jewelry,^[11] aquamarine powder has proven to be a beneficial ingredient in cosmetics. It has a binding and skin protecting function that ensures protection of the skin from external influences.^[33]

Aquamarine	Origin	Size	Location	Description
Dom Pedro aquamarine[34]	Found in Pedra Azul, Minas Gerais, Brazil. Mined in 1980.[35]	10,363 carats	National Museum of Natural History, Washington, D.C.[36][37]	World's largest cut aquamarine. Named after the first two emperors of Brazil, Pedro I and Pedro II.[38]
The Roosevelt Aquamarine[39]	Given to Eleanor Roosevelt in 1936.	1,298 carats	Franklin D. Roosevelt Presidential Library and Museum	Given to US First Lady Eleanor Roosevelt when she and President Roosevelt visited Brazil. It is known as the second largest cut specimen of aquamarine, behind the Dom Pedro.[38]
The Hirsch Aquamarine	Once owned by Louis XV.	109.92 carats	Unknown	Once owned by the French Emperor Louis XV.
Queen Elizabeth's Aquamarine Tiara	Given to Queen Elizabeth in 1953.	Unknown	British royal family	In 1957, she purchased this tiara from Garrad, to match another aquamarine set she had received from Brazilian President Getúlio Vargas in 1953 as a coronation gift.[38]
Meghan Markle's Aquamarine Ring	Once owned by Princess Diana.	>30 carats	Meghan Markle	Received from Prince Harry during their wedding, this ring once belonged to Princess Diana.[38]
The Schlumberger Bow	Owned by Tiffany & Co.	148.5 carats	Field Museum of Natural History, Chicago.	Was part of a collection owned by Tiffany & Co. Purchased in 1984 to be placed in the Field Museum.[13]

• List of gemstones
• List of minerals