This article explains a few things about Are Diamonds Really Rare?, and if you’re interested, then this is worth reading, because you can never tell what you don’t know.
When you walk into a jewelry store and see
all the diamonds in all of the various settings
that are for sale, it is difficult to realize that
diamonds are [...]

The following article includes pertinent information that may cause you to reconsider what you thought you understood. The most important thing is to study with an open mind and be willing to revise your understanding if necessary.
Diamonds are measured in Carat Weight.
One carat weighs 200 milligrams. If a
diamond is referred to as four grains, this
also [...]