Diamonds are the most important, iconic and expensive gemstones of our century.  Many factors such as improved faceting technology, newly discovered mines, industry consolidation and marketing have made it so.

There are many natural properties of diamond that make it special to us.

Hardness (Durability)

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 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 its 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. This explains why your diamond ring still sparkles even though it hasn’t been cleaned in years, while your semi-precious gemstones look cloudy when dirty.

Dispersion (Rainbows)

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 Zircon, sphene (titanite) 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 because of more standardization.

Here is an illustration of diamonds of different values.

low value diamond

medium value diamond

high value diamond

highest value diamond

Low ValueThis is a .32 carat, SI clarity, J color diamond.  Such a diamond can be bought for a few hundred dollars. High ValueThis 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.

Diamond Care:

Diamonds are attracted to grease. This unusual quality of diamonds is used in diamond mining – a conveyor belt is coated with grease and run through a mix of stone and those that stick to it are the diamonds… What does this mean for you?  It means your diamond is also going to want to stick to grease, including soap, lotion, etc.  so you will want to clean it often to keep it sparkling.  To clean it, anything that cuts grease is good – dish-washing soap and and old toothbrush will work well.

Here is a cute “test” you can take, offered by the GIA: http://howtobuyadiamond.gia.edu

Still have questions? Post it in our gemstone forum