The Physical Properties of Diamonds

Diamonds are forever and are a girl’s best friend, as you already know. However, have you ever wondered what makes diamonds so valuable and so renowned throughout the world? Diamonds are appreciated for their rarity, particularly flawless high carat diamonds that often sell for millions of dollars. Diamonds have been sought by mankind for hundreds of years, not necessarily because they were rare, but because they were unparalleled in terms of beauty and durability.

Diamond refers to the allotrope of carbon, where carbon atoms are arranged in what is called an isometric-hexoctahedral crystal lattice. When mankind first saw such a naturally formed product, they immediately recognized its potential for creating beautiful jewelry as well as its use in industrial applications. Why was this substance known as diamond so potentially valuable? The high dispersion of light was very striking as was the hardness of the material.

The Strength of a Diamond

In fact, a diamond is the hardest known material to be naturally produced. A common error is to say that a diamond is the hardest or most durable material in the world. However, it the diamond is merely one of the hardest substances known to man. The four other substances that rank higher (namely aggregated diamond nanorods, ultrahard fullerite, and rhenium diboride) are all man-made. Therefore, a diamond can only be rightfully called the hardest natural substance in earth’s existence. Diamonds make very effective abrasives and in fact, can only be scratched by other diamonds or substances rated as a harder character. The definition of hardness is defined by the resistance to scratching. The hardness of a diamond has been known throughout history and has been ranked a 10 out of 10 on the Mohs scale of mineral hardness (created in 1812 by German mineralogist Friedrich Mohs).

Another aspect to consider is the toughness of a diamond. This is slightly different from hardness, as it involves the ability of the diamond to resist breakage from heavy impact. Unlike hardness, the toughness of a naturally produced diamond is about standard—impressive to other types of gems but less durable than various materials used in engineering. Therefore, just because a diamond lasts forever does not mean that it is “unbreakable.” Some diamonds may actually be fragile to concentrated blows, depending on their macroscopic geometry.

This all means that a diamond can hold polish very well and retain the “luster” for a very long time–as the girl says, even forever. This explains the use of a diamond as a gemstone, as it can be worn daily by wed or soon-to-be-wed couples without the threat of scratching or breaking. A diamond’s thermal conductivity is another impressive characteristic, as it measures anywhere from 900 to 2300 Wm K. The melting point of a diamond is 3820 K, or 6420 degrees Fahrenheit. The density of a diamond can range anywhere from 3.15 to 3.53 g/cm3, with extremely pure diamonds reaching the highest points. Another characteristic of the diamond is in electrical conductivity. Some blue diamonds have been known to serve as very effective semi-conductors, and naturally produced ones at that. Other colored diamonds have proven to be very effective electrical insulators.

The Color of a Diamond

Diamonds can form in very different colors, from white to blue to green to pink or even black. The most common colors of diamond are yellow and brown, with violet, green, orange and red being among the most rare colors. The black diamonds that you read about are not actually black, but contain dark-colored inclusions that influence the appearance of the overall gem. All of the colored gems you see will contain some impurities or defects, because this is what causes the coloration in the first place. This is why the most expensive diamonds usually have a transparent and colorless appearance–they have no major flaws and are considered “pure.” Scientifically speaking, the reason for a diamond impurity is because a carbon atom in the lattice has been replaced. Nitrogen is a common replacement that causes impurity and may result in a yellow coloration. This is one of the most commonly found diamonds, and this is no surprise when you realize that these are among the most flawed. (Though not necessarily any less beautiful) Because of the complexities of color, the Gemological Institute of America classifies a color scale from D or colorless to Z, which is light yellow.

The physical properties of a diamond is what defines this substance, a naturally made item that can just as well be used in industry and engineering as it can be displayed in a jewelry case. A diamond is near impossible to scratch, difficult to break and can last for millenniums if not indeed “forever.” In fact the diamonds that mankind finds on the earth’s surface date back to billions of years ago. When you handle a diamond you can be sure that it well symbolizes something truly special.

Other articles of interest:

• Diamonds Come in Many Varieties
• A Brief History of Diamonds
• The Diamond Lover’s Vacation
• The Mystique of Diamonds