When considering your purchase of an antique engagement ring, there are four things to take into consideration-carat weight, color, clarity and cut.
Carat is a measure of weight for a diamond. The European Cut diamond as compared to a Round Brilliant of the same millimeter size can weigh as much as 10-15% more because of cut. (See the Cut paragraph for more details.) Most diamonds are under one carat and are measured in points. One hundred points are equal to one carat, (1.00ct) whereas three quarters of a carat is equal to, (.75ct). Diamonds are usually purchased in “magic” numbers according to The Gemological Institute of America. Those “magic” numbers are .25ct, .50ct, .75ct and 1.00ct. As it relates to size, a 1.00ct engagement ring vs. a .90ct is not discernable to the naked eye, but its cost is considerably more expensive. When purchasing your diamond ring, just stay under the carat mark and you will save quite a bit of money.
Color is graded from D-F which is colorless to Z which is light yellow.
G-J Near Colorless
K-M Faint Yellow
N-Z Very Light to Light Yellow
After Z Fancy Yellow
A great place to be when purchasing your diamond is in the Near Colorless range because the eye can hardly differentiate between Colorless to Near Colorless. Your European Cut vintage engagement ring can easily go to the M in the color range because the cut of this diamond camouflages its color beautifully and it will face up white.
Clarity ranges from Flawless to highly Imperfect according to The Gemological Institute of America and the grading takes into consideration the size of the inclusion, crystals or blemishes and its location. Grading is done with 10x magnification and assumes it is graded by a trained diamond specialist. The grading is as follows:
IF Internally Flawless
VVS Extremely difficult to see
VS Slightly difficult to somewhat easy to see
SI Easy to see or eye visible
I Imperfect diamonds, heavily included and can affect durability
A great place to be all things considered is in the VS to SI1 range.
Cut refers to the faceting and not to shape – oval and princess cut, for example. Basically, when referring to the cut of a diamond, we can focus our thoughts on two different styles, the Round Brilliant and the European Cut diamond. The European Cut diamond, from the 19th century and earlier, is characteristically different from the 20th century Round Brilliant Cut. It has fewer facets and is hand cut in a way that enhances color and gives beautiful brilliance. The table of a European Cut is smaller than the Round Brilliant. The crown angles are higher making it heavier on top than the Round Brilliant of the same millimeter size. The thicker girdle is not faceted. The pavilion is deeper and the culet is open. It does not come to a point as it does today. It was designed to bring light in from the top and reflect back if looking at the diamond from the top. All of these factors taken into consideration improve the color. The European Cut is very popular now, as the Round Brilliant Cut diamonds cannot replace the unique and romantic antique diamonds in vintage settings today.
Round Brilliant Cut diamonds were created by Marcel Tolkowsky and are cut to very specific calculations. They are more cone-shaped than the European Cut diamonds and have 58 or more facets. The table is larger and the girdle, which is the section that separates the table from the pavilion, is faceted. The pavilion is not as high and it does not have a culet. It comes to a point on the bottom. Polish and symmetry are also taken into consideration and every facet has the potential to change the rays of light giving it a lot of brilliance.