Diamonds are a form of carbon. Origin of name: From Greek for invincible. A diamond is a crystal completely made of the element carbon, except for trace impurities like boron and nitrogen. The arrangement of the carbon atoms or its crystal structure within the diamond gives it its unique properties. As well as being the hardest known material, it is also the least compressible, and the stiffest material, the best thermal conductor with an extremely low thermal expansion, chemically inert to most acids and alkalis, immensely strong, rigid structure with a very high melting point (3800°C) diamond is the hardest known natural substance. Diamonds are found in Africa (Angola, Botswana, South Africa, Congo, Zimbabwe, Tanzania), Asia (Russia and India), North America (Canada and USA) and Oceania (Australia)
Color: it is rare to find diamonds are truly colorless.
Diamonds come in all colors but these natural Fancy Color Diamonds are rare and can be very expensive. One out of 10,000 normal diamonds is a fancy color diamond. The color of a fancy colored diamond is measured differently to a normal diamonds. The grading scale is based on the intensity of the color.
Sapphire is any color of the mineral corundum other than red, those are called ruby (see above), corundum is composed of aluminium oxide. Sapphires tend to be translucent or transparent and have high amounts of refraction. The most desirable sapphires are generally those with an intense blue color with plenty of sparkle and life. Various shades of blue result from titanium and iron substitutions in the aluminium oxide crystal lattice. Some sapphires show a 3-point or 6-point star or asterism. These sapphires are cut into cabochons to display this effect. They can be found in Brazil, Tanzania, Sri Lanka, Kashmir, Thailand, Madagascar and Australia.
Color: Shades of blue.
Sapphires are mainly known for their shades of blues, but they come in an assortment of colors.
Color: all colors across the spectrum including white and black.
N.B. It should be noted that many Sapphires can be treated to enhance or change their color. They are heated or irradiated to produce stronger colors such as greens, yellows or even blues. While the color of Sapphires can be changed by intense heat and radiation, it is stable for daily wear jewelry.
Aquamarine belongs to the gemstone family of Beryls. Origin of name Latin "aqua"meaning water and "mar"sea. Legend has it that Mermaids tails were made of aquamarine. Aquamarine is usually free of inclusions and possesses a superior brilliance. The more intense the colour of an Aquamarine, the higher its value.The principle supply of aquamarine stones comes from Brazil, Russia, Afghanistan, India and Pakistan
Color: pale blue to light greenish
Emerald is a valuable Beryl that owes its color to chromium or vanadium, which make it the bright green. Origin of name emerald is said to be a Sanskrit word meaning green (Sanskrit is a classical language of India). Emeralds can have many inclusions and flaws so can be brittle and liable to break.The value of an emerald depends on cut, colour, clarity and carat. Clear stones with vibrant colour command the highest prices. It is found in Brazil, Pakistan, Russia, East Africa, India, Madagascar and Columbia, at this point in time the best emeralds come from Colombia.
Color: Emeralds come in many shades of green and bluish green.
N.B. Many emeralds are treated to hide surface-reaching breaks and improve transparency.
Ruby is the red variety of the mineral called Corundum which is composed of aluminium oxide (any other color of corundrum is a sapphire, see below). The red colour is caused mainly by chromium and titanium. It is natural for rubies to have imperfections in them, including colour impurities and inclusions of rutile needles known as "silk. Origin of name comes from ruber, Latin for red. Some rubies show a 3-point or 6-point star or asterism. These rubies are cut into cabochons to display this effect. Natural occurring rubies are very rare and extremely rare in large sizes over 3 carats. They can be found in many regions around the world from India, to East Africa, to South America, the Hindu Kush and a few deposits in the United States.
Color: pinkish red or deep, rich red color
N.B. Almost all rubies today are treated in some form (of which heat treatment is the most common practice) and rubies which are completely untreated and still of excellent quality command a large premium. Improvements used include color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them.
Pearl is a smooth, lustrous, chiefly calcium carbonate organic gemstones. Natural pearls are nearly 100% nacre, a protective mother of pearl coating that is secreted to protect the organism for a foreign body that has entered the shell. Natural or real pearls come mainly from oysters, although there are other bi-valve molluscs which can produce them. Almost any species of bivalve or gastropod is capable of producing pearls. However, only a few species, such as the famous pearl oysters, can create pearls which are highly prized. Cultured pearls are produced by artificially introducing a foreign object into the fleshy part of oysters, which become coated with nacre in a similar manner to natural pearls. Imitation pearls, simulated pearls, have been produced for many years. Pearls are found in the regions of Japan, China, Tahiti, Australia, Indonesia, Philippines, USA and Burma.
Color: white or cream, but the color can vary according to the natural color of the nacre in the various species of mollusc used. Can also be black or various pastel shades. Pearls (especially freshwater pearls) can be dyed yellow, green, blue, brown, pink, purple, or black
Hardness: 3.5 to 4.0
N.B.To test if a pearl is natural, rub across the edge of your teeth; real pearl feels rough, simulated feel smooth.