How big is a Brian Gavin one carat diamond?
One of the most frequent questions that we get asked at Brian Gavin Diamonds is how big is our one carat diamond. The average diameter of a one carat round ideal cut diamond is approximately 6.50 millimeters, but most people don't have a visual reference to that measurement in millimeters.
A simple way to get an idea for the size of a one carat round ideal cut diamond is to look at the outside diameter on a standard #2 pencil because it has an average outside diameter of 6.50 mm, which is pretty close to the average outside diameter for most of the one carat round diamonds featured in the Brian Gavin Signature and Brian Gavin Blue collections.
Understand that the average outside diameter will be slightly different for all round brilliant cut diamonds, because the measurements vary from stone to stone, and factors such as the measurements for total depth, crown height, pavilion depth, and girdle thickness must also be taken into account.
How to calculate the average diameter of a diamond:
The average outside diameter of a diamond is based upon the first two measurements provided under the "measurements" section of a diamond grading report, this measurement will be stated in the format of something like 6.48 - 6.51 x 3.97 mm, the first two sections of numbers represent the measurements across the surface of the diamond as measured from north to south and east to west, the last measurement represents the distance from the top of the table facet, through the diamond, down to the culet which is the bottom point of the diamond.
The average outside diameter of the diamond is determined by adding the first two measurements together and then dividing them by two, e.g., 6.48 + 6.51 = 12.99 and then dividing that number by 2 = 6.495 which would be rounded off to 6.50 mm.
Factors that affect diamond carat weight:
As mentioned previously, the total depth of the diamond, as well as other factors such as the crown height, girdle thickness, and pavilion depth, all affect the appearance of a diamond in terms of how it will face up and what the outside diameter will be.
One of the benefits of a diamond from the Brian Gavin Signature or Brian Gavin Blue collections, is that the proportions of the diamond are optimized to maximize light return, but also so that each section of the diamond is balanced to maximize the outside diameter.
Round brilliant cut diamonds which are not cut to the center range of ideal proportions, are often cut extremely deep in terms of total depth, as a result of having too much crown height, girdle edges which are too thick, and pavilion sections which are too deep, this results in an outside diameter which is significantly smaller than a one carat diamond from Brian Gavin.
Since diamonds are sold by carat weight, it makes sense to buy a diamond which has proportions which are optimized to deliver maximum light performance, while ensuring that the diamond will face up as large as possible for the carat weight.