The reason that diamonds are special in the gem world is that they are the most durable. They are the hardest natural substance in the world (10 on Moh's Hardness scale). This means that almost nothing can scratch a diamond (except another diamond). This does not mean, however, that they are invulnerable. Diamonds have cleavage planes, like most minerals, so that if dropped or hit at a particular angle, they will crack or shatter. Therefore, it is important that a diamond is faceted and set in a way that protects its vulnerable areas.Luster (Shine)
Another characteristic that makes diamond inherently valuable is it s luster: it reflects light very well. A polished facet of a diamond is almost mirror-like in its reflection. You can take a piece of faceted glass (e.g. Swarovski crystal) or a faceted piece of light colored quartz and examine the facets in white light (facets are the tiny polished planes that are on the surface of a cut gemstone). You will see that the facets of the diamond are almost white, whereas the glass or quartz facets are somewhat transparent.Dispersion (Rainbows)
And finally, diamond is special as a mineral because it makes rainbows. This is called dispersion, and it is uniquely high in diamonds. (Other gemstones with high dispersion include_once Zircon, and CZ). When you twirl a diamond around in the light, you will catch glimpses of fire, flashes of colored light. There are many resources and highly available information on how to evaluate a quality diamond. There are diamond grading institutions that issue certificates for diamonds, detailing exactly what you are getting. Because of this, shopping for a diamond requires less savvy, and in a sense there is less risk. At the same time, a gemstone shopper can feel the fun part of evaluating stones is slightly reduced. But a good jeweler can keep the process exciting. The diamond characteristics used to define quality are the same for diamonds as they all for all gemstones, only for diamond they are more exactly categorized.Here is an illustration of diamonds of different values.
|Low Value This is a .32 carat, SI clarity, J color diamond. Such a diamond can be bought for a few hundred dollars.||High Value This is a 1.37 carat, VS clarity, F color diamond. You can buy a diamond like this for under $10,000.||Very High Value Here is a 5 carat diamond with VVS clarity, and G color. This diamond can be found for sale at around $200,000.||Highest Value Here is a fancy blue 45 carat diamond. It is so valuable, that it possibly priceless. It lives in the Smithsonian Museum and is called the Hope Daimond.|