Sapphire

Sapphire, like ruby, is a variety of corundum; it gains its color from one or more metallic oxides that appear in the mineral as impurities. The Lone Star, a star sapphire cut in England in 1889, weighs 9,719.5 carats, or about four and a half pounds.

Trace amounts of other elements such as iron, titanium or chromium can give Pink-orange, purple, pink, yellwo, corundum blue or greenish colour. Pink-orange corundum are also sapphires, but are instead called ‘padparadscha’.

Because it is a gestone, sapphire is commonly worn as jewelry. Sapphire can be found naturally, or manufactured in large crystal boules. Because of its remarkable hardness, sapphire is used in many applications, including infrared optical components, watch crystals, high-durability windows.

Ruby

Ruby is pink to blood-red gemstone. The red colour caused mainly by the presence of the element chromium. Its name came for ruber, which means red in Latin.

Other varieties of gem quality corundum are called Sapphires. Ruby is considered one of the four precious stones, together with the sapphire, the emerald and the diamond.

Prices of rubies are primarily determined by color. The brightest and most valuable "red" called pigeon blood-red, commands a huge premium over other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions will indicate that the stone has been treated. Cut and carat (size) also determine the price.

Rubies have been in Afghanistan, Combodia and Theiland. They are rarely found in Sri Lanka where pink sapphires are more common.

Yellow chrysoberyl

Yellow greenish to light yellow or brown chrysoberyl, which contains ferric iron as an impurity. Has an absorption spectrum band at first part of the violet at 444 nm, which can be seen in some chrysoberyl cat's-eye.

Cat’s-eye

Cat’s Eye is one the world’s few precious stones. It is Japanese manga by Tsukasa Hojo.

Cat’s Eye chrysoberyl is classified as a phenomenon stone because its beauty and value depend on a unique gemological effect. Simply defined, chatoyancy is the name given to the shimmering light reflections from densely packed rutile fibers inside the stone.
Body color is also important when choosing a Cat’s Eye chrysoberyl. While stones range in color honey-brown to apple-green, the amber colors are more popular with men and the greener colors with women, although this is not a hard-and-fast rule.

The best-cut Cat’s Eye chrysoberyls show a effect when light is shone on one side and the stone rotated. The stone will divide into perfect blinking halves of light and dark. It is really quite spectacular.

Cat’s Eye chrysoberyl is very rare and only two countries “Brazil and Sri Lanka” currently produce it.

Cat's Eye has also aired in a number of countries outside Japan, including France, Canada, Germany, Italy, Philippines and China.

Alexandrite

This rare gemstone, its variety displays a colour change which is also called alexandrite effect, depends upon light along with strong pleochroism. Alexandrite results from small scale replacement of aluminum by chromium oxide, which is responsible for alexandrite’s characteristic green to red colour. The ideal colour change would be fine emeral green to fine purplish red, but this is rare.

Beautiful alexandrite in top quality, however, is very rare indeed and hardly ever used in modern jewellery. In antique Russian jewellery you may come across it with a little luck, since Russian master jewellers loved this stone. Tiffany’s master gemmologist George Frederick Kunz (1856-1932) was also fascinated by alexandrite, and the jeweller’s firm produced some beautiful series of rings and platinum ensembles at the end of the 19th and beginning of the 20th century. Smaller alexandrites were occasionally also used in Victorian jewellery from England.

Chrysoberyl

Chrysoberyl gemstone is an aluminate of beryllium. Meaning of Chrysoberyl means ‘A gold white spar.’ Although there is similarity of the names, chrysoberyl and beryl, but they are two compeletly different gemstone. Chrysoberyl is the third hardest natural gemstone and llies between corundum and topaz on the hardness of scale.

Three main varieties of chrysoberyl. Ordinary yellow chrysoberyl, cat's eye or cymophane, and alexandrite. Although yellow chrysoberyl was referred to as chrysolite during the Victorian and Edwardian eras, that name is no longer used in the gemological nomenclature.

Ordinary chrysoberyl is a yellowish-green, transparent to translucent chrysoberyl and has often been referred to in the literature as chrysolite due to the common olive color of many of its gems, but that name is no longer used in the gemological nomenclature. When the mineral exhibits good pale green to yellow color and is transparent, then it is used as a gemstone.

Onyx

Onyx is blended variety of chalcedony, a cryptocrystalline form of quartz. The colour of its bands range from white to almost every colour not included not included shades such as purple or blue. Commonly specimens of Onyx contains colour of white, tan and brown sardonyx is a variant in which the coloured bands sard shades of red than black.

Onyx banded calcite are found in Mexico, Pakistan and other place, and often carved, polished and sold. This material is much softer than true onyx, and much more readily available. The majority of carved items sold as ‘Onyx’ today are this carbonate material.

Agate

Agate is also known as chalcedony. The stone was given its name by a Greek philosopher and naturalist Theophrastus, who discovered the stone along the shore line of the river Achates. The agate has been recovered at a number of ancient sites, indicating its widespread use in the ancient world.

It is a stone that has been used for centuries as gems and as precious materials for the production of ornaments or small sculptures. The name chalcedony comes from Calcedon, or Calchedon, an ancient port on the Sea of Marmara, in Asia Minor. Ornamental materials used to be mined in that area and it was an active trading center for many gems. Various forms of agate used to be used extensively for bases and handles of gold items such as goblets, and for stone inlay work.

Tiny crystals of quartz interlock to form agate and because of this, it is always opaque to translucent. Agate is an excellent material for cameos as the contrast between the different layers is used to heighten the relief. Agate's value was quite high in antiquity, when it was one of the main gemstones used. Now its value is fairly low, except for the rare green form called chrysoprase.

Bloodstone

Bloodstone, green jasper dotted with bright red spots of iron oxide, was treasured in ancient times and served for a long time as the birthstone for March. This attractive chalcedony quartz is also known as heliotrope because in ancient times polished stones were described as reflecting the sun: perhaps the appearance of the gem reminded the ancients of the red setting sun, mirrored in the ocean.

Even today, finely pulverized bloodstone is used as a medicine and aphrodisiac in India. Perhaps that explains why it is now rather difficult to find fine specimens of bloodstone on the market. Bloodstone is mined in India, Australia, and the United States.

Medieval Christians often used bloodstone to carve scenes of the crucifixion and martyrs, for which reason it was also dubbed the martyr's stone. According to the legend about the origin of bloodstone, it was first formed when drops of Christ's blood fell and stained some jasper at the foot of the cross.

Chalcedony

Chalcedony is a cryptocrstalline form of silica, composed of very fine intergrowths of the minerals quartz and moganit. These are both silica miners, but they differ in that quartz has a trigonal crystal structure, whilst moganite is monoclinic. It can assume a wide range of colours, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black.

Chalcedony and its named varieties are well represented in various birthstone charts and can be found for all the months except January, April, and November. It is also listed as a birthstone for all the Zodiac signs except Taurus, Cancer, Scorpio and Sagittarius.
The term chalcedony is derived from the name of the ancient Greek town Chalkedon in Asia Minor.

Chalcedony, which is found worldwide, is the name for a group of stones made of a microcrystalline or cryptocrystalline variety of quartz, which means the quartz crystals are too small to be seen without high magnification.

In jewelry usage, the name Chalcedony is usually applied only to the light blue translucent and waxy form. Other stones in this group are know as agate, Petrified dinosaur bone, bloodstone, petrified wood, woodfire agate, carnelian, sardonyx, tiger’s eye, chrysocolla, oxyx and chrysoprase.

Golden Beryl

Gold looks great against the skin. Golden gems look even better. Perfect with earth tones and just the right contrast with hot bright pastels, golden beryl is a versatile addition to every jewelry wardrobe.

Golden beryl is one of the many hues of the "gemstone" mineral beryl It can range in colors from pale yellow to a brilliant gold. Unlike emeral, golden beryl has very few flaws.

The term "golden beryl" is sometimes synonymous with heliodor, but in the strict sense, golden beryl refers to pure yellow or golden yellow shades, while heliodor refers to the greenish-yellow shades.

Golden beryl was discovered in Namibia. Now a day Golden beryl is mainly found in Brazil and Madagascar. The fine gems with an intense banana-peel yellow are rare.

As Golden beryl is largely unknown, it is much more affordable than aquamarine. Because the match of iron and beryl is a complementary, the crystals often grow large and lovely, so cut stones can be sizable. The largest faceted golden beryl, 2,054 carats, is on display at the Smithsonian Institution in Washington D.C.

Emerald

Emerald is a Greek name “smaragdos” which means green stone.

It tends to have numerous inclusions and surface breaking fissures.Unlike diamond, where the loupe standard i.e. 10X magnification is used to grade clarity, emerald is graded by eye. Thus, if an emerald has no visible inclusion to the eye it is considered flawless. Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated, "oiled", to enhance the apparent clarity. Eye-clean stones of a vivid primary green hue with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone command the highest prices. This relative crystal non-uniformity makes emeralds more likely than other gemstones to be cut into cabochons, rather than faceted shapes.

It's common knowledge in the trade that most emeralds are treated; some are filled with oils, such as cedar wood. Others are filled with polymer resins to hide surface-reaching breaks and improve transparency. As with most treatments there's nothing wrong with this as long as the buyer knows that the stone they are buying is treated.

The birthstone for May, emerald is steeped in superstition and lore. It is the symbol for immortality and the symbolization of faith.

Aquamarines

Aquamarine has delicay with its blue or turquoise colour. It is closely related to emerald. Colors vary, and in addition to blue, yellow beryl heliodor, rose pink beryl (morganite, red berry and white beryl (goshenite) are also to be found.

Aquamarine is a beryl with a hexagonal crystal a beryllium aluminium 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. Refrative indices range around 1.57 to 1.58.

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.
Some of it are found in Russia. The gem-gravel placer deposits of Sri Lanka contain aquamarine. Clear yellow beryl are from Brazil, is sometimes called aquamarine chrysolite.When corundum presents the bluish tint of typica auamarine.

Aquamarines can be found at Mt. Antero in central Colorado. It has also been found in Wycoming at the Big Horn mountains. In Brazil, there are mines in the states of Minas Gerais, Espirito Santo and Bahia. The Mines of Colombia, Zambia, Madagascar, Malawi, Tanzania and Kenya also produce aquamarine.