The gem of all gems, is in fact nothing but absolutely pure crystalline carbon. Hardness is its forte. This gives it the ability to reflect maximum amount of light and thus maximum brilliance, when perfectly cut. There are four 'C's of a diamond which determine it's value.

# Cut: The better a diamond is cut, the greater will be its brilliance and sparkle.
# Colour: The closed a diamond is to colourlessness, the greater is its value.
# Clarity: Flawless or cleaner the diamond, the greater is it's value.
# Carat: A diamond is weighed in `carat`. A carat equals 200mg in standard metric system. Each carat is further divided into 100 points.

Emeralds come from the family called Beryl. Stones like Aquamarine, Morganite are also from the same family. Emeralds can be found in shades of light to very dark green. Emerald being comparatively soft, it is very rarely found to be free of inclusions or defects. Many a times, better quality or transparency makes the stone look light in colour. Very fine lustre as well as dark colour is rare. It is found mainly in Columbia, Brazil, Zambia, and Zimbabwe.

Ruby and Emerald are the most popular gemstones after Diamond and fall in the next price level as well. The pigeon blood red is supposed to be the best colour for the ruby. But shades from Pink (Sri Lanka) to dark red (Thailand) are also found. More the transparency, better the quality. Best variety comes from Burma. Tanzania and Kenya also produce good rubies. ?Spienel?, an another gemstone, looks very similar to ruby and has physical properties very near to it and is also found in the same mines. Rubies found in India are not of very fine quality and come very cheap.

The most popular gemstone in India. Generally mistaken with Topaz or Citrine and also the yellow coloured American Diamond (Cubic Zirconia). The Blue Sapphire and Ruby along with the Yellow Sapphire form the Corundum family. They have the same basic crystalline systems. Different pigmenting elements give various colours and hence the names. E.g. iron causes yellow colour, chrome causes red (ruby) and combination of iron and titanium gives blue colour. Best varieties are found in Srilanka and Thailand.

Generally the term ‘Sapphire” refers to blue sapphire. This stone is not as popular in India as in Europe and America; where it is set along with diamonds and looks very beautiful. Best varieties are found in Sri Lanka, Burma, Thailand and Australia. Many other blue coloured gemstones like Blue Topaz, Iolite; Spinel, Tanzanite, Tourmaline, Zircon look similar and are used as substitutes.

Like Pearls, Coral is also a sea –product. It also consists of calcium carbonate. Often we hear about coral reefs near shallow sea- fronts. The tree like branches of coral are calcified skeleton remains of sea creatures, called polyps. Corals of deep red colour are most valuable. But one can find shades ranging from pure white to black. Various shapes are carved out of good quality corals.

Cat?s eye effect is an optical effect which looks like a cat?s eyeball. This is caused by inclusions arranged in a parallel manner. Thus, more transparent variety will show the less of the effect. The basic is called ?Chrysoberyl?. Other natural stones like Appetite, Moonstone, Tourmaline etc. also show cat?s eye effect. The best variety comes from Kerala and Orissa.

Pearl is an organic product consisting of calcium carbonate. A seashell produces pearls by depositing layers around a nucleus. There are three basic types of pearls –

• Basara / Venezuela Pearls: This is genuine seawater pearl which is generally shapeless. It is the most durable variety.
  
• Cultured Pearls (Mikimoto Pearl) : It is same in nature as Basara Pearl. Only it is produced under controlled conditions, to get perfectly spherical shape. The process of culturing was developed by Mr. Mikimoto of Japan and even today cultured pearls are known as Mikimoto Pearls.
• South Sea Pearls: This is a variety of cultured pearl having sizes necessarily larger than 10 mm. It comes from North coast of Australia.
• Tahiti Pearls: This variety of big cultured pearls is produced in Tahiti, Islands in Pacific Ocean. Black & Grey colour is its speciality.
• Mabe Pearl: these are composite half round pearls having an attached base made of pearls shell.
• Fresh water Pearls: These pearls are produced in fresh water (mainly in china) and these pearls have largest wholesale market in Hyderabad. These are rice like or flattened or totally shapeless. But due to lack of hardness they ware out very fast and lost lustre. Czeco, Tissue, Semi – cultured are all imitations of pearls made from synthetic material coated with ‘Pearl Paint’

This stone is a part of the garnet family. This stone is found in Sri Lanka and Orissa. The reddish brown colour like the ‘Gomutra’ (cow urine) gives it it’s popular named Gomed.

A purple coloured stone from Quartz family and thus not very costly.

This olive green stone is used by August-born.

This Blue opaque stone comes from Copper ore mine. It contains gold particles.

This is really hardened rubber. When rubber trees got buried due to lava flows, they came under high pressure forming hard stones. Thus many times fossils are found trapped inside them.

This is also called kidney stones and is supposed to cure kidney diseases. It has bands of shades of green in concentric pattern.

Another opaque blue stone. Comes from Persia and is considered very holy by the Tibetans.

This pale blue stone looks like sea water, hence the name. Comes from 'Beryl' family.