Nothing looks more stunning than a diamond engagement ring. The rule of thumb when purchasing diamond engagement rings is to spend approximately two months salary for a quality piece. As with most purchases, people tend to spend more than they originally intended.

To make sure that you don't have to spend more than you have to on your diamond ring, brush up on your knowledge of the four Cs: Clarity (flawlessness), Cut, Color (colorless is usually preferred), and Carat (size). The most important "C" you need to look out for is the cut. The cut makes all the difference in determining how much light is able to enter and refract in the stone.

Different types of cuts include:

The Emerald- This shape is named for its emerald shape, a rectangle with cut corners. It is the most organic shape-the closest to the raw, natural shape of a diamond. This cut is perfect for an engagement ring, because it will hold its value, but also it is not the most highly expensive of diamond shapes. But because it is less faceted than some of the other cuts, it may not look as brilliant, and may dull faster.

The Round Brilliant- The most classic diamond cut, it offers a superior amount of brilliance, due to its many-faceted cut. This is the cut most often chosen for the solitaire, accounting for more than 75% of all diamonds sold.

The Marquise- This is the most expensive of all the brilliant-style shapes, because it is the most fragile. The tapered ends give it a very distinctive look, but makes it more susceptible to wear and tear.

The Oval- A nice alternative to the round, the oval diamond shape disperses light just as brilliantly and because of its hybrid shape, a combination between the pear and the round, it can look larger than the round. It is most flattering to women with small hands, as it gives the illusion of longer fingers.

The Pear- Very close to the Marquise, this shape is tapered and pointed on only one end. Its distinctive shape is lovely, as with the Marquise, but has the same problematic consideration of durability.

The Trilliant- It was first developed in Amsterdam, and the shape is of a wedge or triangle. The fire and brilliance of this cut are due to the amount of facets involved, and the unique shape makes it an adventurous choice.