Diamond certifications were not introduced until the late 1950’s, so a truly antique engagement ring cannot possibly be certified. If a jeweler displaying an antique ring presents a certificate for that ring, it can mean one of three things:
- The ring is not an antique ring, but a modern copy or reproduction
- The ring itself is antique, but the gemstone has been replaced, and it is not the original diamond in the mount
- The antique mount has at some point been damaged, and when it was repaired, the stone was removed and certificated
1. Color: how white a diamond is. The grading system for whiteness, for historical reasons, starts at D-grade (the whitest) going down to Z. As the diamond descends the letter-scale, a yellow, grey, or brown hue will become progressively more noticeable. As a general rule of thumb, if when looking at a diamond with the naked eye, and you can see no hints of color, the diamond is probably going to be an "H" color or better. As a certified jeweler, I would advise anyone to avoid purchasing a diamond below H-grade, regardless of whether you are looking at antique or contemporary rings.
2. Clarity: how many “inclusions” or imperfections does a diamond have inside the stone (the fewer, the better). If you can see any black carbon spots or white feathery inclusions with the naked eye, it is not a high-quality diamond. Such a diamond would be referred to as an “I” or “Si” stone no the clarity grading scale. A desirable diamond is rated either "VVS" or "VS" for clarity, and it is worth looking at the gemstone yourself with the jeweler's loupe (magnifying glass) to see if you can see any inclusions. It is worth noting that modern-day marketers have added an extra grading system ranging from “X” to “triple X”, but this doesn’t pertain to antique jewels.
3. Carat weight: how heavy the diamond is. Diamonds have what is called a “carat premium”; the price of the diamond increases in proportion to the weight ratio, until a noticeable jump at the 1 carat mark. The price ratio then continues until you get to the 2 carat mark, and again there is a spike in price. This pattern continues every time a full carat is crossed in weight.
4. Cut: what gives a diamond its brightness and luster. When a diamond appears sparkly and shiny, it is an indication that the stone has high surface reflection and is cut to the correct proportions. Additionally, internal reflection plays a role: where no light passes through the stone, but is reflected from the back facets back through the diamond's table. In antique engagement rings, because the diamonds are cut by hand, the proportions of the stone give this total light reflection, and even if you take an antique engagement ring out of the bright light it will still have its bright fire and luster. Contrast this with many modern-cut diamonds, which are cut to include a large surface area but no depth. This results in much shine under shop spotlights, which significantly diminishes in natural light. Pay close attention to stones with high “spread” (diamond weight-to-surface spread) ratios, because in a natural light that diamond will lose a lot of its shimmer.
Although antique diamond engagement rings were made before the diamond grading system, don’t let that deter you from purchasing one for your beloved! Antique jewelry was created in a time when they cut the diamonds to make the most of all their natural brilliance in all lights whether it be sunlight, candlelight or spotlights.