Carat Weight
Most people compare carat weight to size. The larger the diamond the more
it weighs. The weight of a diamond is expressed in carats. The word carat
originated from the carob tree or Ceratonia siliqua. The tiny seeds of
this tree are well known for their uniformity and consistent weight. Traditionally
diamonds and gemstones were weighed against these seeds until the system
was standardized, and one carat was fixed at 0.2 grams. One carat is divided
into 100 points. A diamond weighing one quarter of a carat can also be
described as weighing 25 points or 0.25 carats. Points are generally not
used to describe weights over one carat. Here are some examples of different
weights for round diamonds and their corresponding sizes. These may not
be actual size due to your monitor. The approximate girdle diameter is
displayed in millimeters.
How Size Effects Rarity
The rarity of a diamond is greatly affected by its size. The rarity of
a 1.00 carat diamond is much greater than twice that of a .50 carat. Although
it only weighs twice as much, the 1.00 carat is statistically much more
difficult (rare) to mine than the .50 carat. For an easy comparison of
price and size, see the table below. Prices are approximate and based
upon D Color, internally flawless, excellent cut.
