Sunday, January 25, 2009

Clarity: The First C of Diamond Grading

A flawless stone simply means that no flaw can be found even with the use of a 10x jeweler's loupe or 10x microscope. As you go down the scale, the VVS-1 may have one very small inclusion, generally not in the table (which will be covered later) portion of the diamond but possibly on the edge. Again, this flaw is seen only from the front and only on using 10x magnification. It should not be visible to the naked eye.

As we get into VVS-2, there may be more than one flaw with magnification but they're still extremely small. One small inclusion may be in the table area of the diamond.

Into the VS grades, the flaws become larger and more prominent than their VVS cousins. VS2 may have larger flaws or a number of small spots possibly located in the table of the diamond that group together and are almost considered one flaw. They are generally in the same area.

When we talk about 10x magnification, this can be in the form of a jeweler's loupe which is a fairly inexpensive must-have item for anyone serious about stones or a step upward which is the two eyepiece (stereo) microscope, which many jewelers will have on the premises and will let one borrow when perusing their stones.

It is wise to always make sure that the magnification device employed is 1Ox. This is the standard and any variation from this will affect the rating of the stone to a great degree.

Note that flawless VVS and VS rated stones are rated when looking at the stone right side up with a 1Ox magnification device. If you pick up a stone that supposedly falls under one of these ratings and you can see inclusions with the naked eye, you're not looking at a stone that is properly rated.

An Sl-1 rated stone will have inclusions that are very obvious under 1Ox magnification, but should still be borderline visible or not visible when viewed with the naked eye. The Sl-1 stone may have these borderline visible, small dots or inclusions in the table or edge of the stone. An Sl-2 rating will have larger flaws and probably more than one. These will be easily visible to the naked eye.

In the I grades, the stones can be considered either quite flawed or imperfect. Flaws are probably inside the table. There may be flaws of more than one variety, clouds, cracks or groups of black or white carbon spots will be visible. This last group of stones obviously are the least valuable and the least interesting for anyone trying to convert from cash to gems and back again.

Looking backward we can infer several things, the first of which being if you can spot a number of inclusions without the use of magnification device, the stone is going to be graded 1, whether I-1, I-2 or I-3 is open to some subjective effort, but it will be an I rated stone.

If you can't find flaws with your eye alone but they do become visible when using a loupe, one can assume that the stone is an Sl rated stone.

The differentiation between an S stone and a VS stone is that in a VS stone inclusions may not be seen extremely clearly even with the loupe. If the stone is turned over and laid on the flat front part (the face of the stone - this is the table) and one views down from the back of the stone where all the facets come to a point and the flaws are more readily seen here, one can assume it is a VS-2 or above rated stone.

Note this viewing is done under white light and with the stone loose.  It is very difficult to judge any of the 4 C's when the stone is mounted. Mounted stones are not generally considered for investment grade purchases. The stone should be loose and one should be able to turn it freely.

Source: Video Vindicator, 1992, BBS.

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