Diamonds are weighed in units called carats. There are 100 points in one whole carat. If you see something like 0.25 cts, that means that the diamond weighs 25 out of 100 points, or approximately one quarter of a carat. 0.50 points would mean one half of a carat, 0.75 would mean three quarters of a carat,  and so forth. One thing certain to keep in mind is the fact that diamond rough is very rare.  Some gemstones are found in very large pieces and plentiful deposits, but not so with diamonds. The larger the diamond, or the more the carat weight, the more expensive a diamond is going to be because of the rarity of the stone size. Also, when there are a great number of little diamonds, and all of them together equal some amount - let us say 0.50 total carat weight - that is not as rare as a single gem weighing 0.50 carats.  Smaller diamonds are much more plentiful than larger diamonds, and one large diamond is worth much more than several small diamonds put together. Because of this, diamond rough is cut very carefully to maintain as much weight as possible without affecting it's beauty.

 

That diamond is so sparkly! The reason for the sparkle and the spectral
colors viewed in a diamond is the way that the stone is cut.  If a stone has been cut poorly, it will not shine as brighlty as one that has been cut well. 
In the particular case of diamonds, it is especially important to have a
 good cut so that the light that enters it will reflect off of several facets
within the diamond before returning to your eye to display that special
sparkle. GIA has assigned round diamonds cut grades ranging anywhere from poor to excellent.  At Magee Jewelry, we have beautiful and visually stunning diamonds in our custom-made pieces, but not all of them would
earn an "excellent" cut grade from this system of grading, and we are
okay with that.  All of the diamonds that we carry have high cut grade
marks, and it is obvious they do by their displayed brilliance.  After all,
we hand-picked them ourselves and then make mountings for them to
show their individual personalities and sparkle.

The color of a diamond, is the small amount of body color that slightly tints each stone. The color scale starts at D (colorless) and goes to Z - which is a stone that is saturated with a strong body color. Every diamond that falls outside of the Z color range is a fancy-colored diamond.
There is a very slight difference in the color grades, and truly, we find that unless a stone has a fairly strong saturation of body color, it is often very difficult to tell if it has any color at all. When a diamond is graded for color, 
the use of a master stone set is needed to compare the body colors of each stone, and this is because the human mind cannot memorize color. If you know that color is one of the most important deciding factors for your purchase of a diamond, you should compare, side-by-side, two diamonds with different body color. You will probably find that there is very little discernible difference in the face-up appearance of diamonds that have
color in the range before the "L" color grade. We stick to the idea that
if you can see it, and it bothers you, that is when you need to decide if
paying more for a diamond with an upgrade in color is worth the extra cost.
If you cannot see the difference, maybe it is not worth spending the extra money on a diamond that has a slight difference in color.

We think the same principle goes for the clarity grade of a diamond.
If you cannot tell the difference, and you think the stone is beautiful,
should you pay more for an upgrade in clarity? Clarity is the relative
freeness of inclusions in a diamond.  Inclusions can be thought of as
birth marks. They are interuptions in the mineral formation of a stone.
We think that inclusions in any stone, including diamonds, are a little like personality traits; everyone needs a few defining personality traits -
those that distinguish an individual - but personality traits that get too big
and too obvious can be overwhelming. Some stones just have too
much personality for our liking, and you may find that for yourself as well! 

The clarity grade scale is as follows:
 Internally Flawless (IF),
Very, Very Slightly Included (VVS),
Very Slightly Included (VS),
Slightly Included (SI),
and Included (I).

Included (I) diamonds are the only diamonds that display obvious
clarity characteristics to the unaided eye. They have a lot of personality.
In an included diamond (I), you can see the clarity characteristics with your unaided eye, which means that they are obvious without magnification,
and sometimes they can effect the safety of a diamond.  We do carry some Incvluded (I) diamonds, but the clarity grade does not fall below an I1 (the highest Included diamond grade), and we do not carry any diamonds that could be endangered because of inclusions.  A slightly included (SI)
diamond has few clarity characteristics that can only be seen under 10 power magnification - most jewelry stores use a 10 power loupe for this purpose. Most of the diamonds at Magee Jewelry are slightly included (SI) diamonds. They have individual personality, but not too much to be distracting or annoying. Any clarity grade above slightly included (SI), and a person
would need a microscope - and some experience - to see any possible
clarity characteristics.

Carat Weight