What is a Carat

Shopping for diamond or other gemstone jewelry you should evaluate the gem's color, clarity, cut and carat.
The type of measurement used to describe the mass of a gem called carat was applied to diamonds only but now it also applies to most semi-precious and precious stones. We see some confusion in the word carat because gold as well as diamonds is evaluated in carats (karats). Karat doesn't apply to mass and refers to gold which is classed by purity. 10 Karat gold, for example, has the greatest purity than 24 Karat gold.
When we evaluate a gem, the term carat refers to its mass but not to the quality of the gem. Carat weight or size can be measured on the metric scale. Equivalent to one carat is 0.2 grams. If you deal with jewelry with small diamond chips, the carat measurement may evaluate not the each chip but the total carat weight. And small chills are more common and therefore less expensive.

Uncut diamonds which are much larger than cut varieties are full of flaws and must be cut. Jewelry with single large stones is offered at immensely high prices- the larger the carat weight, the rarer and more expensive the diamond is.
A small carat diamond may seem larger because of its clarity, setting and cut. A half-carat diamond is close to perfect and it may be much impressive than one-carat diamond. One-carat diamond has many flaws and each flaw decreases the ability of the stone to reflect light and therefore one-carat diamond is less sparkly.
Buying expensive diamond jewelry you'd better consult your jeweler and shop in trusted jewelry stores.