A gemstone is a mineral or rock, which can be used in jewelry after cutting or faceting and polishing. Gemstones are an important commodity in today’s marketplace. They have been sought after for thousands of years for their beauty, metaphysical properties, and commercial uses. In earlier times there were no such things as synthetic gemstones but today they are quite common.

On the basis of its formation, gemstones are classified into five categories:

– Natural Gemstones
– Genuine Gemstones
– Synthetic Gemstones
– Imitation or Simulated Gemstones
– Treated Gemstones

Common gemstones are classified into two categories:

    * Precious
    * Semi-Precious Stones.

Gemstones those are valued for their beauty and not covered under any one of the four ‘Precious Stones’, Diamond, Emerald, Ruby or Sapphire, are known as Semi-Precious Stones. Semi-Precious Stones are available in all price ranges from low priced to high priced. There are many Semi-Precious Stones. Precious Stones Gemstones those are highly valuable for their hardness and rarity, are known as Precious Stones. Precious Stones are generally expensive in comparison of Semi-Precious Stones.

Diamond

Diamond is also considered as precious gem.

Emerald

Color – Emerald Green to Dark Green
Mohs hardness scale – 7.5 – 8
Mineral Class – Beryl
Source – Found in Columbia, Brazil, Zimbabwe, South Africa, Afghanistan, USA

Ruby

Color – Bright red, brownish-red, purplish-red, dark red
Mohs hardness scale – 9
Mineral Class – Corundum
Source – Found mainly in Burma, Thailand, Sri Lanka and Tanzania.

Sapphire

Color – Blue, Yellow, Green, White, Colorless, Pink, Orange, Brown and Purple
Mohs hardness scale – 9
Mineral Class – Corundum
Source – Found mainly in Sri Lanka, Thailand, Burma, Australia, India, Brazil and Africa

There are many Semi-Precious Stones.

Alexandrite

Color – Dark to Pale Green (color is changed in different forms of lights)
Mohs hardness scale – 8.5
Mineral Class – Chrysoberyl
Source – Found mainly in Russia, Sri Lanka, Brazil, Burma, Madagascar, USA

Amethyst

Color – Purple, Pale lavender to deep reddish purple, bluish violet
Mohs hardness scale – 7
Mineral Class – Quartz
Source – Found mainly in Sri Lanka, Brazil, Burma, Canada, East Africa, India, North America, Russia, Uruguay, Madagascar and Australia

Aquamarine

Color – Blue, Sea-green
Mohs hardness scale – 7.5 – 8
Mineral Class – Beryl
Source – Found mainly in Brazil, Madagascar, Russia, Afghanistan, India, Pakistan, Nigeria, Zambia, Mozambique and USA

Citrine

Color – Light Yellow, Lemon Yellow, Amber-Brown, Brilliant Orange
Mohs hardness scale – 7
Mineral Class – Quartz
Source – Found mainly in South America, Brazil, Madagascar, Argentina, Russia, Scotland and Spain

Garnet

Color – Light Red, Violet, Red, White, Green, Yellow, Brown, Black
Mohs hardness scale – 6.5-7.5
Mineral Class – Quartz
Source – Found mainly in Burma, Sri Lanka, South Africa, China, USA, Tanzania, Madagascar, India and Australia

Iolite

Color – Violet-Blue, Deep Blue, Light Blue-Gray, Yellow-White
Mohs hardness scale – 7 – 7.5
Mineral Class – Cordierite
Source – Found mainly in India, Sri Lanka, Mozambique, Zimbabwe and Brazil

Onyx

Color – Black, White, Black with White bands, Red, Brown
Mohs hardness scale – 6.5 – 7
Mineral Class – Quartz
Source – Found mainly in Madagascar, India, Brazil, United States, Pakistan and Sri Lanka

Opal
Color – Black, White, Gray, Yellow, Red, Orange and Colorless
Mohs hardness scale – 5 – 6.5
Source – Found mainly in Australia, Brazil, Mali, Japan, Russia, USA, Mexico

Pearl
Color – White, White tinted with Cream, Pink, Yellow, Green, Blue, Brown, Purple, or Black.
Mohs hardness scale – 2.5 – 4.5
Source – Found mainly in Persian Gulf, China Sea

Peridot
Color – Yellow Green, Olive, Brownish Green
Mohs hardness scale – 6.5 – 7
Mineral Class – Olivine
Source – Found mainly in Australia, Mexico, Sri Lanka, South Africa, Tanzania, China, Burma, Arizona, USA, Pakistan, Afghanistan

Tanzanite
Color – Deep Blue, Ultramarine Blue, Light Violet-Blue, Purple
Mohs hardness scale – 6 – 7
Mineral Class – Quartz
Source – Found in Tanzania

Topaz
Color – Blue, Brown, Green, Orange, Pink, Red, Yellow, White, Gold, Colorless
Mohs hardness scale – 8
Mineral Class – Topaz
Source – Found mainly in Brazil, Sri Lanka, Burma, Nigeria, USA, Australia, Madagascar and Mexico

Tourmaline

Color – Black, Red, Pink, Blue, Green, Grey and Yellow
Mohs hardness scale – 7 – 7.5
Mineral Class – Quartzite
Source – Found mainly in Brazil, Sri Lanka, South Africa, Nigeria, Zimbabwe, Kenya, Tanzania, Mozambique, Madagascar, Pakistan, Afghanistan, USA