The gemstone or gem are cut and polished for of a mineral crystal that are used to make jewelry or other ornaments. However some non minerals like rocks or organic material are also used jewelry and also considered to be as gemstone as well. The gemstones are considered to be as precious gemstone or semi-precious gemstone. Some of the gemstones are hard but some of them are soft minerals and are used for jewelry because of their luster or its elegant physical properties. The gem makers are called gem-cutter or a lapidary.
There are total 2500 kinds of category of minerals on the planet out of which only 60 are used as the gemstones. Other minerals are not suitable as they are too soft and can be scratched or deformed easily. Gemology is done to make a complete study of each stone, both as it is found in rocks and after that its cutting and polishing.During the formal study of gems both the things are given duo importance. Gemology distinguishes between the crystal structure and the physical properties of the gems. Everyone must have an idea about the gem and its property before buying them. Hardness, specific gravity, crystal shape, optical properties all varies in each gem.
Some of the most common gems are: NEELAM(blue sapphire), PUKHRAJ(topaz), MOONGA (red sapphire), HEERA(diamond), PANNA(emerald), RUBY(manik), MOTI(pearl)and many more. These gemstones are so popular among the people and people do wear them according to their zodiac signs or the ruling planets widely in hindu religion. Some of the islamic peoples do also believes in it. The physical properties like shape, color and some other properties distinguishes the difference between all gemstones.Now lets come to know more about these popular gemstones briefly :
EMERALD(panna) : The most famous and the green colored gemstone is combined with durability and rarity, it is one of the most expensive gemstone. There is a fact about this gem that as paler is the color of emerald, higher is the value. It has a vitreous luster with a transparent image of hexagonal cutting.
PEARL(moti) : The pearl is the organic gem and are formed by living organisms. They are formed into the soft tissue layers of mollusks. They are the composition of calcium carbonate and organic conchiolin. Pearls have been highly valued as gemstones since a relic time. They have an opaque figure with a pearly luster belongs to amorphous crystal system.
DIAMOND(heera) : Diamond is the most precious gem in all known for its hardness, durability, its sparking fire and rarity on the earth. Most of the time diamond used asgem stones are colorless or very fainted colored. Diamond isometric crystal system with a transparent to opaque texture an adamant luster.
TOPAZ(pukhraj) : Topaz is an ideal gem with a very good hardness and color. It is a combination of abundance and availability, that makes it one of the most popular gemstone. The most expensive gem of this range is the Imperial Topaz.The value of the gem increases with deepness of the orange and red color. The most commonly used color of topaz in jewelry is the blue color. It has a orthorhombic crystal system with transparent texture and vitreous luster.
This was a short review on the few gems that what are their qualities and who do they differ with each other. There are still so many facts that are left to know about these gems.