How to choose a gemstone and a piece of jewelry

How to choose a gemstone and a piece of jewelry

Nature of GemstonesFirst, it is essential to have the basic knowledge about the characteristics, colors, clarity, cutting style and the weight of the gemstones you are selecting. Generally speaking, there are two categories of gemstone - precious and semi-precious.Precious stones are Diamond, Ruby, Sapphire, Yellow Sapphire, Emerald and Cat's Eyes.Semi-precious stones are Tourmaline, Peridot, Tazanit, Garnet. Opal, Spinel, Zircon, Aquamarine, Moonstone, Agate, Pearl, Sunstone, etc.The commercial value, hardness, and durability of semi-precious stones are normally less than precious stones.Thailand is one of the world's most important sources of Corundum. the collective gemological name for precious stones like Ruby and Sapphire.



Ruby
Its color ranges from dark red to pink hardness measured in Mohs is 9: reflective index is from 1.762 to 1.770 (+/-0.009 - 0.005}: and specific gravity of 4.00 (+/- 0.10 - 0.05). This precious stone has its origin in countries like Thailand, Cambodia, Myanmar (Burma), Vietnam and Tanzania.

Blue Sapphire

It is another species of Corundum with properties quite similar to Ruby in terms of color, hardness and specific gravity. Its origins are Thailand, Cambodia and Myanmar (Burma).


Yellow Sapphire

As part of the Corundum family. Yellow Sapphire has specifications like 'Blue Sapphire and Ruby, but it is only found mostly in Thailand and Sri Lanka.



Diamond

Discovered mostly in Africa, Australia, Russia and South America, the Diamond is normally colorless, though some come in the shades of light yellow and brown. Its hardness is 10 in Moh measurement; reflective index of 2.417: specific gravity of 3.52 (+/-0.01).

Quality and value of gemstones
The value of a gemstone lies in its beauty, measured by its color, luster, transparency, clarity, perfection of cutting (polishing), size, durability as well as rarity.
Ruby
The most valued Ruby is in pigeon's blood red. The stone with dark to purple red color has a lesser value. The Ruby which yields good transparency is considered more beautiful and has more value than the lesser one. The value of Ruby can also be judged by its clarity which is normally a key characteristic of the stone, and physical site.Another beauty yardstick of Ruby is the "Asterism" or star in the stone that renders it the name of "Star Ruby." The star can be best appreciated from Ruby with a cabo chon shape placed in the light.
Blue & Yellow Sapphire

The highly priced color of Blue Sapphire is "pure" blue not being tainted with green or gray, yet not too dark or black. The most beautiful color for Yellow Sapphire is dark yellow and golden yellow. The popularity of the two shades varies from one market to another, depending on tastes and fashion trends. Blue and Yellow Sapphires with good transparency and clarity command more value with size as another determining factor, though it is easier to find a bigger size of Blue and Yellow Sapphires than Ruby. Like Ruby, Blue Sapphire has the "star" while it is rare to find a star in Yellow Sapphire.
Diamond

More common colors of diamond range from light yellow and light brown while while is rarer (*see color grading table). There are also established clarity levels of diamond (*see clarity table).The bigger the size the higher the value of the diamond. Well-proportioned cut diamond is capable of reflecting light, yield more brilliance and sparkle, thus is more valued.