How Can You Tell if a Diamond is Antique?

Rings are often advertised as “antique vintage engagement rings” or containing an “authentic antique diamond,” but it’s difficult to know what’s true. Finding out if a diamond ring is truly antique or authentic is not a process exclusive to jewelers and technicians.

Below is a guide for determining whether a diamond is antique.

Is My Diamond Antique?

There are five principal methods for antique diamond authentication. These techniques (aside from the last one) can be done at home with little or no professional tools.

1. Determine if the diamond cut is antique
2. Look at the culet of the diamond
3. Identifying the age of the mounting or setting
4. Examining the girdle of the diamond
5. Sending the diamond to a professional for an appraisal

1. Determine the Age of a Diamond by Diamond Shapes

The easiest way to know if a diamond is antique is by examining the actual shape of the diamond. There are hundreds of diamond shapes on the market right now. Almost all of them have been developed within the past 40 years. There are about ten genuinely antique cuts. If the diamond you are examining has a recently developed shape, it obviously can’t be antique.

This technique is the first line of defense when analyzing a loose diamond or even a diamond within a mounting. We recommend first studying our vintage diamond page to determine if the diamond belongs to one of the antique shapes.

Antique Diamond Cuts

Here is a list of the antique diamond cuts:

• Antique Cushion Cut
• Old European Cut
• Old Mine Cut
• Antique Emerald Cut
• Antique Asscher Cut
• Rose Cut Diamond
• French Cut Diamond
• Antique Oval and Marquise Cuts

These diamond shapes listed above may be old. Of course, the diamonds could be recent versions of the diamond shape. To be sure that the diamond (which conforms to the list) is antique, you must move on to technique 2.

Modern Diamond Cuts

Here is a list of the popular diamonds that are not antique:

• Modern Round Brilliant Cut
• Princess Cut
• Radiant Cut
• Heart Shape
• Kite Shape
• Triangle Shape
• Trilliant Cut
• Octagonal Cut | Hexagonal Cut | Pentagonal Cut

If your diamond has any shapes in the second list, you can know with certainty that it is not antique. None of the criteria below will help prove that your diamond is antique. For a diamond to be antique, it must be a shape invented over 100 years ago.

2. Authenticating a Diamond by its Cutlet

When looking at an antique, authentic diamond, the culet is usually one of the top indicators of age.

The culet is the facet at the very bottom of the diamond. The tiny facet runs parallel to the table and is typically easily visible, even to the untrained eye.

Modern diamond cutting techniques enable the jewelers to shave down the bottom culet so it is far too small to see. Even when examining a modern diamond with a loupe it will be very difficult to find the culet. The technology to finely cut the tail-end of a diamond did not exist 100 years ago.

The culet should appear in the center when looking into any authentic antique diamond from above. The culet may be a circle, oval, octagon, or rectangular.

Here are examples of rings with antique diamonds. Note the large cutlets inside of the diamonds.

3. Authenticating a Diamond through its Mounting

An authentic diamond can also be authenticated by examining its setting or mounting. There are so many indications on jewelry that will help reveal its age. Use the jewelry to give you insight into the age of the diamond. Use a diamond loupe to magnify the piece and analyze the jewelry carefully.

Here are some of the things to look out for when determining if the mounting is antique :

• Anniversary dates or birthday dates that are inscribed inside the shank
• Patina or fading on the metal that indicates sufficient age
• Smaller accenting diamonds that are antique
• Antique hallmarks, country export stamps, or company signatures that would indicate age
• Appraisal or certification that indicates the age of the jewelry

Unfortunately, this method is not foolproof. Placing a modern diamond inside an antique piece of jewelry is very easy. The vintage market has many examples of antique jewelry with modern stones.

4. Examining the Diamond’s Girdle

The girdle is the thin section that winds around the side of a diamond and separates the crown from the pavilion. Most diamonds that date after the 1940s will have a polished girdle. If the girdle is not transparent but appears to have a sheen of frost, it will almost certainly be an authentic antique diamond.

This authentication method, however, will only prove if a diamond is antique but won’t prove that a diamond is modern. There are many genuine antique diamonds on the market that have polished girdles. It has become a disturbing trend among jewelers to polish their antique diamonds.

If you want to read our complete guide on understanding the diamond girdle, click here.

5. Send the Diamond to a Professional for an Appraisal

Finally, if all else fails, there is one other option. If identifying an authentic diamond is important to you, find a company that specializes in the certification of antique jewelry.

Jewelry professionals can identify the period of a diamond by examining the shape and facets of the stone. Diamond cuts have evolved from early old mine to today’s brilliant-cut diamonds. Trained professionals can analyze the diamond to determine its approximate age.

Video Tutorial to Tell if your Diamond is Vintage