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Sapphire is a type of the mineral corundum, an aluminium oxide (Al ₂O ₃). Sapphires are the same as rubies, except that they are not red.

Sapphire can be found in the ground or it can be made in large crystal. Blue sapphires are the most famous kind, but they can be many different colors, like amber and orange.

Sapphires have a long history. Tradition says that the tablets of the Ten Commandments were made of sapphire, so strong a hammer could not break them, and would break instead if it hit them. The ancient Persians believed that the earth sat on a big sapphire and that the big sapphire made the sky blue.

A lot of ancient people thought rubies made people calm down, as well as cure their bruises.

Sapphires have been used by kings and queens for a long time as a symbol of luck, virtue, wisdom, and holiness. Princess Diana and Princess Anne both received sapphire engagement rings and the British Crown Jewels are full of large blue sapphires, the symbol of kind and wise rulers.

Sapphires represent September. It symbolizes telling the truth and doing what you said you would.

Sapphire is actually just corundum and is one of the hardest minerals on the hardness scale. Since sapphire is the second hardest mineral in the hardness scale, it is sometimes used as a polishing tool.

This mineral is found in gem gravel deposits. These deposits are formed from the heat of metamorphic or igneous rock plateaus. The places where sapphire is formed abundantly are Myanmar, Thailand, India and Sri Lanka. The most costly and beautiful sapphires are shipped from Kashmir, India. In other words, sapphire is mostly found in Asia. Recent findings of sapphire have taken place in Australia, Kenya, and Tanzania.

Sapphire was the first mineral to be lab grown in a strategy called "flame fusion". Another strategy, slightly harder to use, "flux growth" was used to lab grow sapphire.

Heating yellow, light yellow, or colorless sapphire from 1500-1900oc can turn into a dark yellow, gold, golden brown, orange, or a reddish brown colored sapphire. There is a specific kind of sapphire called Star sapphires have whitish pieces of rutile or silk as some call it. Star sapphires can be heated to remove the blue color of sapphire and can be heated even more to get the blue color back and remove the white silk.

U of Texas. "corundum." ruby and sapphire notes. U of Texas, 24 Aug. 2012. Web. 30 Oct. 2012. < http://www.geo.utexas.edu/courses/347k/redesign/gem_notes/ corundum/corundum_triple_frame.htm>.

Gait, Robert I. "Sapphire." World Book Advanced. World Book, 2012.Web. 4 Dec. 2012.

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Sapphire is a type of the mineral corundum, an aluminium oxide (Al 2O 3). Sapphires are the same as rubies, except that they are not red. Sapphire can be found in the ground or it can be made in large crystal. Blue sapphires are the most famous kind, but they can be many different colors, like amber and orange.

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You're happy with yourself and your life. You don't feel the need to make changes.

Old-school myths

Some people thought rubies contained the spark of life. Many believed that the gems glowed from within and that royalty and gods used rubies to light their homes. That also meant that the stones couldn't be stolen, because they'd shine through the thieves' clothing. A ruby supposedly brought good health, cured bleeding, guarded against wickedness, and foretold bad luck.

Rock-solid facts

Rubies are a red form of the mineral corundum. All other colors of corundum are sapphires. Large gem-quality diamonds, emeralds, and sapphires are scarce, but rubies are the rarest of all.

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Emerald

General

Category

Beryl variety

Formula
(repeating unit)

Be ₃Al ₂(SiO ₃) ₆

Crystal symmetry

(6/m 2/m 2/m) - Dihexagonal Dipyramidal

Unit cell

a = 9.21 Å, c = 9.19 Å; Z = 2

Identification

Formula mass

537.50

Color

Green shades

Crystal habit

Massive to well Crystalline

Crystal system

Hexagonal (6/m 2/m 2/m) Space group: P6/mсc

Cleavage

Imperfect on the [0001]

Fracture

Conchoidal

Mohs scale hardness

7.5-8

Luster
Vitreous

Streak

White

Diaphaneity

Transparent to opaque

Specific gravity

Average 2.76

Optical properties

Uniaxial (-)

Refractive index

n ω = 1.564-1.595,
n ε = 1.568-1.602

Birefringence

δ = 0.0040-0.0070

Ultraviolet fluorescence

None (some fracture filling materials used to improve emerald's clarity do fluoresce, but the stone itself does not)

An emerald is a mineral rock and a variety of beryl. It is the birthstone of someone whose birthday is in the month of May. It is a green rock. The emerald is one of the most valuable gems, along with the ruby, the opal, topaz, the diamond, and a sapphire.

Properties determining value

Emeralds, like all colored gemstones, are graded using four basic parameters-the four Cs of connoisseurship: color, clarity, cut and carat weight. Before the 20th century, jewelers used the term water, as in, "a gem of the finest water", to express the combination of two qualities: color and clarity. Normally, in the grading of colored gemstones, color is by far the most important criterion. However, in the grading of emeralds, clarity is considered a close second. A fine emerald must possess not only a pure verdant green hue as described below, but also a high degree of transparency to be considered a top gem.

In the 1960s, the American jewelry industry changed the definition of emerald to include the green vanadium-bearing beryl. As a result, vanadium emeralds purchased as emeralds in the United States are not recognized as such in the UK and Europe. In America, the distinction between traditional emeralds and the new vanadium kind is often reflected in the use of terms such as "Colombian emerald".

In gemology, color is divided into three components: , saturation, and tone. Emeralds occur in hues ranging from yellow-green to blue-green, with the primary hue necessarily being green. Yellow and blue are the normal secondary hues found in emeralds. Only gems that are medium to dark in tone are considered emeralds; light-toned gems are known instead by the species name green beryl. The finest emeralds are approximately 75% tone on a scale where 0% tone is colorless and 100% is opaque black. In addition, a fine emerald will be saturated and have a hue that is bright (vivid). Gray is the normal saturation modifier or mask found in emeralds; a grayish-green hue is a dull-green hue.

Emeralds tend to have numerous inclusions and surface breaking fissures. Unlike diamonds, where the loupe standard, i.e. 10× magnification, is used to grade clarity, emeralds are graded by eye. Thus, if an emerald has no visible inclusions to the eye (assuming normal visual acuity) it is considered flawless. Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated ("oiled", see below) to enhance the apparent clarity. The inclusions and fissures within an emerald are sometime described as jardin (French for garden), because of their mossy appearance. Imperfections are unique for each emerald and can be used to identify a particular stone. Eye-clean stones of a vivid primary green hue (as described above), with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone, command the highest prices. The relative non-uniformity motivates the cutting of emeralds in cabochon form, rather than faceted shapes. Faceted emeralds are most commonly given an oval cut, or the signature emerald cut, a rectangular cut with facets around the top edge.

Treatments

Most emeralds are oiled as part of the post- lapidary process, in order to fill in surface-reaching cracks so that clarity and stability are improved. Cedar oil, having a similar refractive index, is often used in this widely adopted practice. Other liquids, including synthetic oils and polymers with refractive indexes close to that of emeralds, such as Opticon, are also used. These treatments are typically applied in a vacuum chamber under mild heat, to open the pores of the stone and allow the fracture-filling agent to be absorbed more effectively. The U.S. Federal Trade Commission requires the disclosure of this treatment when an oil treated emerald is sold. The use of oil is traditional and largely accepted by the gem trade, although oil treated emeralds are worth much less than un-treated emeralds of similar quality. Other treatments, for example the use of green-tinted oil, are not acceptable in the trade. Gems are graded on a four-step scale; none, minor, moderate and highly enhanced. These categories reflect levels of enhancement, not clarity. A gem graded none on the enhancement scale may still exhibit visible inclusions. Laboratories apply these criteria differently. Some gemologists consider the mere presence of oil or polymers to constitute enhancement. Others may ignore traces of oil if the presence of the material does not improve the look of the gemstone.

Emerald mines

Emeralds in antiquity have been mined in Egypt since 1500 BCE, and India, and Austria since at least the 14th century CE.

Colombia is by far the world's largest producer of emeralds, constituting 50-95% of the world production, with the number depending on the year, source and grade. Emerald production in Colombia has increased drastically in the last decade, increasing by 78% from 2000 to 2010. The three main emerald mining areas in Colombia are Muzo, Coscuez, and Chivor. Rare "trapiche" emeralds are found in Colombia, distinguished by ray-like spokes of dark impurities.

Zambia is the world's second biggest producer, with its Kafubu River area deposits (Kagem Mines) about 45 km (28 mi) southwest of Kitwe responsible for 20% of the world's production of gem quality stones in 2004. In the first half of 2011 the Kagem mines produced 3.74 tons of emeralds.

Emeralds are found all over the world in countries such as Afghanistan, Australia, Austria, Brazil, Bulgaria, Cambodia, Canada, China, Egypt, Ethiopia, France, Germany, India, Italy, Kazakhstan, Madagascar, Mozambique, Namibia, Nigeria, Norway, Pakistan, Russia, Somalia, South Africa, Spain, Switzerland, Tanzania, the United States, Zambia, and Zimbabwe. In the US, emeralds have been found in Connecticut, Montana, Nevada, North Carolina, and South Carolina. In Canada, in 1997 emeralds were discovered in the Yukon.

Synthetic emerald

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 Chatham, likely involving a lithium vanadate flux process, as Chatham's emeralds do not have any water and contain traces of vanadate, molybdenum and vanadium. The other large producer of flux emeralds was Pierre Gilson Sr., whose products have been on the market since 1964. Gilson's emeralds are usually grown on natural colorless beryl seeds, which are coated on both sides. Growth occurs at the rate of 1 mm per month, a typical seven-month growth run producing emerald crystals of 7 mm of thickness.

Synthetic emeralds are often referred to as "created", as their chemical and gemological composition is the same as their natural counterparts. The U.S. Federal Trade Commission (FTC) has very strict regulations as to what can and what cannot be called "synthetic" stone. The FTC says: "§ 23.23(c) It is unfair or deceptive to use the word "laboratory-grown," "laboratory-created," "[manufacturer name]-created," or "synthetic" with the name of any natural stone to describe any industry product unless such industry product has essentially the same optical, physical, and chemical properties as the stone named."

Emerald in different cultures, and emerald lore

Emerald is regarded as the traditional birthstone for May as well as the traditional gemstone for the astrological signs of Cancer.

One of the quainter anecdotes about emeralds was told by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America. On one of Cortez's most notable emeralds he had the text engraved, Inter Natos Mulierum non sur-rexit mayor ("Among those born of woman there hath not arisen a greater," Matthew 11:11) which referred to John the Baptist. Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pearl (to which he dedicated a work, A beautiful and incomparable pearl), and even for the death of King Charles IX of France, who died soon afterward.

The chief deity of one of India's most famous temple, the Meenakshi Amman Temple in Madurai, is the goddess Meenakshi, whose idol is traditionally thought to be made of emerald.

Emerald crystal (about 1 cm) in calcite matrix, Muzo, Colombia

A 5- carat emerald from Muzo with hexagonal cross-section

Gachalá Emerald, one of the largest gem emeralds in the world, at 858 carats (171.6 g). Found in 1967 at La Vega de San Juan mine in Gachalá, Colombia. Housed at the National Museum of Natural History in Washington, D.C.

Related pages

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In Spanish: Esmeralda para niños

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Diamond

General

Category
minerals

Formula
(repeating unit)
C

Strunz classification

01.CB.10a

Identification

Formula mass

12.01 g/mol

Color

Typically yellow, brown or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple and red.

Crystal habit
Octahedral

A diamond (from the ancient Greek αδάμας - adámas "unbreakable") is a re-arrangement of carbon atoms (those are called allotropes).

Diamonds have the highest hardness of any bulk (all one type) material. Because of this, many important industries use diamonds as tools for cutting and polishing things. Many of them are clear, but some of them have colors, like yellow, red, blue, green and pink. Diamonds of a different color are called "fancies".

Big diamonds are very rare, and are worth a lot of money. Only 20% of diamonds are fit for jewellery. The other 80% are of lower quality. Those lower quality diamonds are called industrial diamonds, and are used to make things like drill bits and diamond saws. Even if a diamond is not of gem quality, it still has a value because it is very hard.

Cut and faceted diamonds can be attractive hence their use in jewellery.

Diamonds are very effective electrical insulators, but also very good conductors of heat.

On Mohs scale of mineral hardness, diamonds are scored as 10 (the highest score possible).

Formation of diamonds

There are natural and synthetic diamonds. The Earth makes natural diamonds, and people make synthetic diamonds.

Diamonds are the hardest natural substance known to man. Diamonds are made of pure carbon, the same chemical element as graphite, fullerene, and coal. But diamonds are very hard and in crystalline form. It is commonly believed that diamonds are formed from coal, but this is not true.

Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kilometres (93 and 155 mi) in the Earth's mantle, although a few have come from as deep as 800 kilometres (500 mi). Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently (tens to hundreds of million years ago), they were carried to the surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites.

Small synthetic diamonds are made for abrasive s. Large synthetic ones are even more expensive to make than to find and dig up, so people don't make large synthetic diamonds.

Where to find diamonds

People find diamonds where volcanoes were a long time ago. They sometimes find tiny ones at the site of a meteorite strike. Sometimes people find diamonds on the top of the ground. But in places like South Africa, they must dig deep down into a diamond mine to get diamonds. Diamonds were first found in India.

The most familiar uses of diamonds today are as gemstones used for adornment, and as industrial abrasives for cutting hard materials. The markets for gem-grade and industrial-grade diamonds value diamonds differently.

In the 20th century, experts in gemology developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds: these are its mass in (a carat being equal to 0.2grams), cut (quality of the cut is graded according to proportions, symmetry and polish), color (how close to white or colorless; for fancy diamonds how intense is its hue), and clarity (how free is it from inclusions). A large, flawless diamond is known as a paragon.

Trading in diamonds

For many decades the trading of diamonds was controlled by the De Beers group of companies, who controlled most of Africa's rich diamond mines. However, in the late 1980s and early 1990s, new diamond mines opened in Canada and Australia that De Beers wasn't able to control. When the USSR collapsed in 1991, many cheap Russian diamonds entered the market, overwhelming De Beers and their efforts to control it. De Beers still runs most of Africa's diamond mines, but their mines now only produce about one third of the world's diamonds.

Diamond cutting

Mined rough diamonds are converted into gems through a multi-step process called "cutting". Diamonds are extremely hard, but also brittle and can be split up by a single blow. Therefore, diamond cutting is traditionally considered as a delicate procedure requiring skills, scientific knowledge, tools and experience. Its final goal is to produce a faceted jewel where the specific angles between the facets would optimize the diamond luster, that is dispersion of white light, whereas the number and area of facets would determine the weight of the final product.

Several possible shapes are considered. Some of them may be considered as classical, such as round, pear, marquise, oval, hearts and arrows diamonds, etc. Some of them are special, produced by certain companies, for example, Phoenix, Cushion, Sole Mio diamonds, etc.

Occasionally, large thefts of diamonds take place. In February 2013 armed robbers carried out a raid at Brussels Airport and escaped with gems estimated to be worth US$50M (£32M; €37M). The gang broke through a perimeter fence and raided the cargo hold of a Swiss-bound plane. The gang have since been arrested and large amounts of cash and diamonds recovered.

The identification of stolen diamonds presents a set of difficult problems. Rough diamonds will have a distinctive shape depending on whether their source is a mine or from an alluvial environment such as a beach or river-alluvial diamonds have smoother surfaces than those that have been mined. Determining the provenance of cut and polished stones is much more complex.

The Kimberley Process was developed to monitor the trade in rough diamonds and prevent their being used to fund violence. Before exporting, rough diamonds are certificated by the government of the country of origin. Some countries, such as Venezuela, are not party to the agreement. The Kimberley Process does not apply to local sales of rough diamonds within a country.

Diamonds may be etched by laser with marks invisible to the naked eye. Lazare Kaplan, a US-based company, developed this method. However, whatever is marked on a diamond can readily be removed.

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Diamond General Category minerals Formula (repeating unit) C Strunz classification 01.CB.10a Identification Formula mass 12.01 g/mol Color Typically yellow, brown or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple and red. Crystal habit Octahedral A diamond (from the ancient Greek αδάμας - adámas "unbreakable") is a re-arrangement of carbon atoms (those are called allotropes).

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You're devoted to those you care about. Friends and family can always count on you.

Old-school myths

In ancient Egypt the topaz's golden glow was said to come from the sun god Ra, and the stone was supposedly a powerful amulet against harm. Other legends proclaimed that a topaz cleared people's thinking, increased strength, and warned of poisoned food or drink. It supposedly cured insomnia and asthma, and stopped bleeding.

Rock-solid facts

Topazes come in a wide range of colors. Many of them are golden; some are pink, green, or colorless.

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Represents pure love

Your affection for those you love is clear. You're not embarrassed by hugs-even from your parents in front of your friends!

Old-school myths

An emerald can melt a snake's eyes! Well, that's what people used to believe. They also thought these gems would relax your eyes if you looked through them. Other beliefs: Emeralds stopped bleeding, cured fevers, and kept the wearer calm. They also supposedly held powers for predicting the future.

Rock-solid facts

Emeralds are sometimes found inside shale, a rock with a very fine grain. Like aquamarines, they're a form of the mineral beryl. These gems are a light to deep green.

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Represents enduring love

You're quick to make up after arguing with someone in your family or group of friends. You don't carry grudges.

Old-school myths

People associated the sparkle of diamonds with romance, mystery, power, greed, and magic. Many once believed that they were made by bolts of lightning.

Rock-solid facts

Diamonds develop deep in the ground under great pressure. The gems are the crystalline form of carbon. (Another form of carbon is graphite, the lead in your pencil.) Diamonds are the hardest naturally occuring substance on Earth.