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.