Birthstones make an ideal gift for birthdays, or any gift-giving occasion. These jaw dropping stones are inherently personal and carry a great deal of sentiment. The American National Association of Jewelers developed the official list of birthstones back in 1912.

There are several factors that determine the value of a birthstone. It’s helpful to know what to keep an eye out for before you begin shopping.

Weight, color, clarity and the quality of the cut all come into play when establishing gemstone value. The cut actually describes how the stone is faceted, rather than the stone’s shape. Gemstone weight is measured in carats. The greater the carats, the greater the value.

When jewelers describe a stone’s clarity, they’re referring to the absence of flaws, such as cracks, fissures, nicks and small pieces of other minerals that are incorporated in the stone.  Every natural gemstone has a flaw of some sort, but when they can’t be detected under ten times magnification, the stone receives a high clarity grading.

In general, the closer a stone is to a pure color, the higher its value. White diamonds, for example, are the most valuable. This is an excellent gift option for anyone with an April birthday.

The cut of a birthstone also affects its value. Stones that are poorly cut might lose their brilliance, so be sure to find a retailer that carries expertly cut birthstones. It’s important to note that that not all birthstones are cut. Opals (October), sapphires (September)  and rubies (July), for example, are all polished instead.

Keep these simple factors in mind before you pick out birthstone jewelry, and you’re sure to find a beautiful gift that will be treasured for years to come.