Diamond Carat Weight
The carat of a diamond refers to the weight of the stone, rather than the dimensions,
with one carat being the equivalent of one-fifth of a gram. Units smaller than one carat
are measured in points, with 100 points equal to one carat.
The carat weight of course impacts the size of the stone, but it is important to
understand that two diamonds of the same carat weight can measure significantly
different across the top, depending on the proportions of the cut. This surface
measurement is how the diamond is viewed when set and gives the overall impression of
The proper diamond cut proportions allow the maximum return of light, delivering
superior fire and sparkle while maximising the visible surface area. A poorly cut
diamond of the same carat may carry most of that weight in the pavilion, or lower part
of the stone, which will make the diamond appear smaller than its actual weight and
significantly less brilliant than the well-cut equivalent.
Steven Stone Tip
“If you would like to purchase a 1ct diamond and optimise your engagement ring budget,
we recommend choosing a well-made 0.90ct round diamond which measures 6.25mm in width,
the same physical size as an average 1ct diamond.”
Important Carat Weight Information
It is a common misconception that all 1ct diamonds appear the same size. This is not the
case, as not the entire diamond is visible from the top down. The percentage of hidden
carat weight, or “depth percentage”, determines the surface area of your diamond that is
visible when set, and there are strict parameters for a well-cut stone. For example, a
well-made round brilliant cut diamond of 1ct in weight should measure between 6.4mm to
6.5mm in width.
It is possible to find a 1ct diamond which measures as low as 5.9mm across, and such low
dimensions would immediately indicate that the diamond is poorly made. Steven Stone
deals only with the top 1% of diamonds and a stone of this quality would fail to meet
our stringent standards for superlative brilliance. When comparing prices, please ensure
you compare the measurements as well as the carat, in order to compare like-for-like, as
poorly made diamonds are inevitably less desirable and therefore cheaper than a well-cut
If you would like to purchase a 1ct diamond but find it falls outside your engagement
ring budget, we recommend choosing a well-made 0.90ct round diamond which measures
6.25mm in width, rather than settling for a poorly made 1ct stone. Choosing a
beautifully proportioned diamond of 0.90ct will give the same surface area and presence
as an average 1ct stone and will still possess the same sparkle, fire and brilliance as
the more expensive option.
If you would like additional guidance or help in choosing the perfect diamond for an
engagement ring, wedding ring, or any piece of diamond jewellery, please feel free to
call our diamond experts on 0800 080 3535 or contact us using the form below.