Emerald

The name emerald derives from Greek smaragdos. It means "green stone" and, in ancient times,  referred not only to emeralds but also probably to most green stones.

Emerald is the most precious stone in the beryl group. Its green is incomparable, and is therefore called "emerald green." The coloring agent for the "real emerald" is chrome. Beryls that are colored by vanadium ought to be called​​​​ "green beryl" and not emerald. The color is very stable against light and heat, and alters at 700-800 degree C. The color distribution is often irregular; a dark slightly bluish green is most desired.

Only the finest specimens are transparent. Often the emerald is clouded by inclusions. These are not necessarily classified as faults, but are evidence as to the genuineness  of the stone as compare with with synthetic and other imitations. The expert refers to these inclusion as jardin ( French -Garden ).
The physical property, especially the density, refractive index, and double refraction, as well as the pleochroism, vary according to source area. All emeralds are brittle and combined with internal stress, sensitive to pressure; care must be taken in heating the. They are resistant to all chemicals which are normally used in the household.

Deposits Emeralds are formed by hydrothermal processes associated with magma and also by metamorphism. Deposit are found in biotire schists, clayshales, in lime-stones, wtih pigmatites.

Mining is nearly exclusively from host rock, where the emerald has grown into small veins or on wall of cavities. Alluvial placer are very unlikely to come about as the density of emerald is near that of quartz. Therefore, rare secondary deposits are mostly formed by weathering.

Significant deposits are in Colombia, especial​​y the Muzo mine northwest of Bogota. First mined by native tribes, the Muzo deposit was abandoned and rediscovered in the 17th century. The mine yields fine quality stones of a deep green color. Mining apart from shafts , is mainly by step form terraces. The emerald bearing, soft broken rock is loosened with sticks, lately also through blasting or with bulldozers, and the emeralds picked out by hand. the host rock is a dark carbonaceous limestone. Accompanying minerals are albite, apartite, arangonite, barite, calcite, dolomite, fluorite, and pyrite.

Another important Colombian deposit, the Chivor Mine, is northeast of Bogota. It was also mined by Native Americans. The host rock is gray-black shale and gray limestone. It is mined in terrace, and also from shafts.

During recent decades further emerald deposits, which promise to be successful, have been found in Columbia. There is always a high demand for the rare, so called Trapiche emerald found exclusively in Colombia, a wheel like growth of several prismatic crystals. Only a third of the Colombian emeralds are worth cutting Stones larger than nut size are usually low quality or broken.

In Brazil there are various deposit in Bahia, Goias, and Minas Gerais. Stone are lighter than Colobian ones, mostly yellow green, but they are often free of inclusions. Through deposits newly discovered since the beginning of the 1980s, Brazil has become one of the most important suppliers of emeralds.

Since the second half of the 1950s, emerald deposits have been explored in Zimbabwe. Most important is the Sandawana mine in the south. Crystals are small, but of very good quality.

In the northern Transvaal (South Africa ), emeralds are mined by modern methods using machinery ( Cobra and Somerset Mines ). Only five percent of the production is of good quality. Most stone are light or turbid and only suitable for cabochons.

Emerald deposits were discovered in 1830 in Russia in the Urals north of Yeka

Aquamarine

Aquamarine ( Latin-water of the sea) is so named because of its seawater color. A dark blue is the most desired color. The coloring agent is iron. Lower qualities are heated to 400-450 degrees C to change them to the desired, permanent aquamarine blue. Higher heat will lead to discoloration. Care must be taken when making jewelry Color can also be improved with neutron and gamma irradiation, but these changes do not last. Aquamarine is brittle and sensitive to pressure. Inclusions of fine, oriented hollow rods or aligned foreign minerals rarely cause a cat's-eye effect or aster-ism with six-ray stars with a vivid sheen.

Deposits The most important deposits are in Brazil, spread throughout the country. The well-known deposits in Russia ( the Urals ) seem to be worked out. Other deposits of some commercial significance are in Australia ( Queensland ), Burma ( Myanmar ), China,  India, Kenya, Madagascar, Mozambique, Namibia, Nigeria, Zambia, Zimbabwe, and the United States. The host rock is pegmatite  and coarse grained granite as well as their weathered material.
The largest aquamarine of gemstone quality was found in 1910 in Marambaya, Minas Gerais (Brazil). It weighed 243 lb ( 110.5kg ), was 18 in ( 48.5 cm ) long and 15.5 in ( 42 cm ) in diameter, and was cut into many stones with a total weight of over 100,000 ct. There have been finds weighing a few tones, but these aquamarines are opaque and gray, not suitable for cutting.
The preferred cuts are step ( emerald ) and brilliant-cut with rectangular or long oval shapes. Turbid stones are cut en cabochon ore are used for necklace beads.

Possibilities for Confusion with eudase, kyanite, topaz, tourmaline, zircon, and glass imitation. Synthetic aquamarine can be produced but is uneconomical. The "synthetic aquamarine" sold in the trade is really aquamarine-colored synthetic spinel.

Famous Sapphire and Possibilities for Confusion

Large sapphires are rare. They are sometime named in the same way as famous diamonds. The American Museum of Natural History ( New York) owns the "Star of India" perhaps the largest cut star sapphire (536ct); also the "Midnight Star" a black star sapphire (116ct). The "Star of Asia" a star sapphire weighing 330ct, is owned by the Smithsonian Institution in Washington D.C.
Two famous sapphires (St. Edward's and the Stuart sapphire) are part of the Lincoln, and Eisenhower have been carved out of three large sapphire, each weighing roughly 2000ct.

Sapphire can be confused with various stones. The blue sapphire looks similar to benitoite, indicolite, iolite, kyanite, spinel, tanzanite, topaz, and zircon, as well as blue glass.
Some imitation are made from doublets-blue cobalt glass with a crown of garnet or crown of green sapphire and a pavilion of synthetic blue sapphire. Lately, doublets have appeared using two small natural sapphire. Star sapphire is imitated by using star rose quartz with blue enamel on a flat back; alternatively the star is engraved on the flat back of a synthetic cabochon or on glass.
Synthetic sapphire was produced with properties identical to the natural stone at the beginning of this century. Since 1947 synthetic star sapphire of gem quality have been sold.

December Gemstones

December-Turquoise, blue topaz and tanzanite represent a happy life that is filled with good fortune. Headaches may be relieved or prevented. Ancient practitioners believed that turquoise would actually change color when the wearer was ill or in danger.

The history of Turquoise.

What exactly are Turquoise? The word Turquoise is derived from the Greek word "Turkois" meaning "Turkish" because it was first brought from Turkey. Turquoise is formed over millions of years by a chemical reaction that occurs when water leaks through rocks which contain specific minerals such as copper and aluminium. The percentage of the minerals in the rock dictate the shade of the turquoise.

Turquoise meaning.

 Is regarded as a love charm. It is also a symbol of good fortune and success, and it is believed to relax the mind and to protect its wearer from harm. Turquoise rings, in particular, are thought to keep away evil spirits.

The history of Blue Topaz.

The word “topaz” is believed to derive from the Sanskrit word “tapas,” which can mean fire, heat, and passion. Others believe “topaz” comes from the Greek word “topazos,” which means “to search.” In 1969, Texas named blue topaz as its official state gem after miners discovered a small deposit of natural blue topaz underground.

Blue Topaz meaning.

Of all the precious stones in the world, blue topaz is the perfect fit for intellectuals. Writers, artists, and scholars give blue topaz meaning by wearing it because it is indeed made for them, promoting higher thinking and cognition. Other feelings attached to blue topaz are serenity, friendship, fidelity, integrity, and gentleness. Just looking into its calm, cool shade of sparkling blue can make you breathe a sigh of relief.

The history of Tanzanite.

Tanzanite is the blue/violet variety of the mineral zoisite (a calcium aluminium hydroxyl Sorosilicate) belonging to the epidote group. It was discovered in the Mererani Hills of Manyara Region in Northern Tanzania in 1967, near the city of Arusha and Mount Kilimanjaro. Tanzanite is used as a gemstone, and naturally formed tanzanite is extremely rare, still found only in the Mererani Hills.

Tanzanite meaning.

Tanzanite is called a "stone of magic" that helps with spiritual awareness and psychic insight. It is also sometimes called the "workaholic's stone".  This is because it helps you slow down and take it easy. This in turn, brings success in more areas of life. It relieves stress and depression, and enhances composure, poise, and harmony. Tanzanite is also said to transmute negativity. Physically it is said in healing folklore and crystal healing to be beneficial for stress related illnesses and high blood pressure in particular.  Note that healing crystal meanings are spiritual supports to healing and are not prescriptions or healthcare information. Tanzanite is related primarily to the throat and third eye chakras.

Deposits of Sapphire

Host rock of sapphire are dolomotized lime stones, marble, basalt, or pegmatite. It is mined mainly from alluvial deposits or deposits formed by weathering, rarely from the primary rock. Production methods are usually very simple. The underground gem-bearing layer is worked from hand -dug holes and trenches. The separation of clay, sand, and gravel is done by washing out the gemstones due to their higher density. Final selection is made by hand. Sapphire is much more common than ruby, as the substances which lend color to sapphire are more in Australia, Myanmar, Sri Langka, and Thailand.
Australia deposits have been known since 1870. The host rock is basalt; the sapphire are washed our of the weathered debris. Quality is modest. Under artificial light, the deep blue stones appear inky, blue green, nearly black; lighter qualities have a green tint. In recent decade black star sapphires have been found in Queensland. Accompanying minerals are pyrope, quartz, topaz, tourmaline, and zircon. Since 1918 good blue qualities have been found in New South Wales.
The alluvial deposits in upper Myanmar near Mogok are partially worked with modern methods and yield rubies and spinels as well as sapphires. The host rock is pegmatite. In 1966 the largest star sapphire was found here, a crystal of 63,000 ct (281l/12.6kg ).

Sapphire have been found in Sri Langka since antiquity. The deposits are in the southwest of the island in the region of Ratnapura. The mother rock is dolomotize limestone, which is enclosed in granite gneiss. There are also 10-20-in (30-60 cm) thick river gravel placers ( called illam locally) that are exploited from a depth of 3-33 ft ( 1-10 m). Sapphires are usually light blue, with a tinge of violet. There are also yellow and orange ( Padparadscha ) varieties as well as green, pink, brown, and nearly colorless stones. also star sapphire. Accompanying minerals are apatite, epidote, garnet, quartz, ruby, spinel, topaz, tourmaline, and zircon.

There are two sapphire deposits in Thailand: one in the region of Chantaburi, southeast of Bangkok, the other one near Kanchantaburi, northwest of Bangkok. The host rock is marble and/or basalt; placers and deposits formed by weathering are mined. The stone are of good quality in various colors, including star sapphire. Blue sapphire have a deep color, but tend to have a tings of blue-green.

The most desired sapphire used to come from Kashmir ( India), where the deposits were situated at a height of 16,500 ft (500 m) in the Zaskar mountains. 

Production varied since 1880, and the deposits have apparently been worked out. The host rock is kaolin-rich pegmatite in crystalline schist. The decomposition product yields sapphire of deep cornflower-blue color, often with a silky sheen. Most stones sold today as Kashmir sapphire come from Myanmar.

In the late 1800s sapphire deposits were discovered in Montana( United State). The host rock is andesite dikes. Mining is carried out on the dike rock, also from weathered material. Color of sapphire varies and is often pale blue or steel-blue. Mining has been interrupted repeatedly since the end of the 1920s,  but has been steadier in recent years.

There are also significant sapphire deposit in Brazil, Cambodia, China, Kenya, Madagascar, Malawi, Nigeria, Pakistan, Rwanda, Tanzania, Vietnam, and Zimbabwe. Isolated star sapphire have found in Finland.

Sapphire

The name sapphire ( Greek-blue) used to be applied to various stones. In antiquity and as late as the Middle Ages, the name sapphire was understood to mean what is today described as lapis lazuli. Around 1800 it was recognized that sapphire and ruby are gem varieties of corundum. At first only the blue variety was call sapphire, and corundum of other colors ( with the exception of red) were given special, misleading names, such as "Oriental peridot" for the green variety and "Original topaz" for yellow type.

Today corundum of gemstone quality of colors except red are called sapphire. Red varieties are called rubies are call rubies. The various colorless sapphire qualified by description, e.g., green sapphire or yellow sapphire . Colorless sapphire is called leuko-sapphire ( Greek-white), pinkish orange sapphire Padparadsha (Sinhalese for ''Lotus Flower'').

There is no definite demarcation between ruby and sapphire. Light red, pink, or violet corundum are usually called sapphire, as in this way they have individual values in comparison with other colors. If they were grouped as rubies, they would be stones of inferior quality. The coloring agents in blue sapphire are iron and titanium; and in violet stones, vanadium. A small iron content results in yellow and green tones; chromium produces pink, iron, and vanadium orange tones. The most desired color is a pure cornflower-blue. In artificial incandescent light, some sapphires can appear to be ink-color or black -blue.

Through heat treatment at temperatures of about 3100-3300 degree F (1700-1800 degree C), some cloudy sapphire, non distinct in color, can change to a bright blue permanent color.
Hardness is the same as ruby and also differs clearly in different directions ( an important factor in cutting). There is no fluorescence for all sapphires.
Inclusion of rutile needles result in a silky shine; oriented, i.e., aligned, needles cause a six-ray star sapphire .

Famous Rubies

Ruby is one of the most expensive gems, large rubies being rarer than comparable diamonds. The largest cuttable ruby weighted 400ct; it was found in Burma and divided into three parts. Famous stones of exceptional beauty are the Ewardes ruby (167ct) in the British Museum of Natural History in London, the Rosser Reeves star ruby (138ct) in the Smithsonian Institution in Washinton, D.C., the De Long star (100ct) in the American Museum of Natural History in New York, and the Peace ruby (43ct), thus called because it was found in 1919 at the end of World War I.
Many rubies comprise important parts of royal insignia and other famous jewelry. The Bohemian St. Wenzel's crown (Prague), for instance, holds a non faceted ruby of about 250ct. But some gems , thought to be rubies, have been revealed as spiniels, such as the ''Black Princes's ruby'' in the English State Crown and the ''Timur Ruby'' in a necklace among the English crown jewels. The drop- shaped spinels in the crown of the Wittelsbachs dating from 1830 were also originally thought to be rubies.

                                                                    Black Princes's ruby
Today rubies were cut in the countries where they were found. Because the cutters usually aim for maximum weight, the proportions are not always satisfactory, so that many stones have to be recut by dealers in other countries. Transparent qualities are cut in step and brilliant cut; less transparent stones, en cabochon or they are formed to carving. Only synthetic rubies are used for watches and bearings, formerly the most important technical application for natural stones.
Possibility for confusion with almadite, pyrope, spinel, topaz, tourmaline, and zircon. Since the beginning of the 20th century, there have been synthetic rubies with gemstone quality; these resemble natural ones especially in their chemical, physical, and optical properties. But most of them can be recognized by their inclusions as well as by the fact that they. in contrast to natural rubies, transmit shortwave ultraviolet light.
Numerous imitations currently are on the market, especially glass imitations and doublets. These have a garnet crown and glass underneath. There are many false names in the trade such as Balas ruby (=spinel), Cape ruby (=pyrope), and Siberian ruby (= tourmaline).