Diamond Introduction « BACK
Diamond is ultimate gemstone & source of fascination since ancinet times. They are the hardest ,the most imperishable,and the brilliant of all precious stones. The word "diamond" come from the greek word "adamas" meaning "unconquerable ", "unbreakable", "unalterable", or "proper", it is one of the best-known and most valued gemstones. Diamonds have been known to mankind and used as decorative items since ancient times, some of the earliest references can be traced to India .Diamonds were born in the earth billions of years ago. They are one of natures miracles firmed under extreme heat and pressure in circumstances that can never be repeated whilst we live on this planet. A diamond is an allotrope of carbon , where the carbon atoms are arranged in a variation of theface centered cubic crystal structure called a diamond lattice.
A diamond has the highest hardness and thermal conductivity of any bulk material.Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities,this results in the clear, colorless appearance of most natural diamonds. Diamond also has relatively high optical dispersion (ability to disperse light of different colors), which results in its characteristic luster. Excellent optical and mechanical properties, combined with efficient marketing, make diamond the most popular gemstone.
Most natural diamonds are formed at high-pressure high-temperature conditions existing at depths of 140 to 190 kilometers (87 to 120 mi) in the Earth mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years (25% to 75% of the age of the Earth). Diamonds are brought close to the Earth surface through deep volcanic eruptions by a magma, which cools into igneous rocks known as kimberlites and lamproites.
Diamonds are very difficult to find and also to mine. The millions of dollars that go into exploration and then only a small percentage are gem quality determine the obvious answer that not only are they are rare but command an appropriate price.
The Diamond Structure
A diamond is made up of two key sections, the Crown and the Pavilion. Their structure and relationship to each other in the form of table and depth percentages have the biggest impact on the diamond’s sparkle.
The round brilliant cut has been used as an example, because with most other diamond shapes (“fancy cut” diamonds) the cut grading is more complicated (hence why their cut grading does not appear on certificates such as GIA).
Diameter: Width of the diamond at the widest point of the girdle (in fancy cut diamonds, the smallest diameter is used).
Table: The largest facet at the top
Crown: The top part of the diamond between the girdle and the table
Girdle: The narrow band at the diamond’s widest point
Pavilion: The bottom part of the diamond between the girdle and the culet
Culet: The fact at the bottom tip (preferable when not visible to the naked eye)
Depth: The height of a diamond from the table to the culet