Diamonds really are a girls best friend, but there are many choices when it comes to diamonds. There are different cuts, shapes, clarity and color. It is important to know what you are looking at when it comes to diamonds and what you really want! Many companies that sell rings will be able to talk you through the different variances of diamonds, but here is some great information to know before you go into a store to look or buy a ring. Guys, it is also important for you to know what you are buying when it comes to any diamond ring, earrings or necklace. As a person with very strong opinions, it may be best to talk to your girlfriends mother, sister or friends to try and get the exact cut she wants. The worst thing you can do is get a diamond your future wife hates!
Here is a great explanation of the different diamond shapes from http://engagementrings.lovetoknow.com/wiki/Diamond_Shapes
Emerald: The emerald shape features a rectangular diamond with trimmed corners. Flaws may be more obvious in this shape and clarity is critical because it has fewer facets to reflect light and hide minor defects. Emerald shapes are popularly set with multiple side stones to provide balance to the elongated shape. 
Pear: This shape is also referred to as a teardrop diamond. Although pear or teardrop diamonds are popular as pendants and earrings, they are also considered an excellent choice for engagement rings. Because of the unbalanced shape, they are not usually set with elaborate accent stones, though a sleek pear shape can create the illusion of slimmer fingers. 
Heart: The heart-shaped diamond is considered more of a novelty and isn't commonly used for engagement rings. A heart shape is more popular for pendants and earrings, but can be found in selected engagement rings, particularly in gemstone rings. The cut can be difficult to make, so you'll want to examine this diamond thoroughly before you purchase it to locate hidden flaws 
Marquise: Elegant and traditional, the marquise is a slim oval shape with tapered, pointed ends. The center stone is usually set parallel to the finger, and it is frequently enhanced with small accent stones along either side. This shape is extremely popular for bridal sets. 
Radiant: This square-shaped diamond has barely trimmed corners to enhance its brilliance, making it essentially a square version of an emerald shape but with a blend of facets usually found in round stones. It can be hard to find however, and is not commonly used for engagement rings because of its scarcity. 
Princess: The princess diamond is also square, but the corners are not trimmed. It is a very popular diamond for engagement rings, particularly rings with three or more stones using a princess gem as the center stone. This can be a less expensive shape of diamond because it follows the stone's natural crystalline shape and may be easier to cut. Color is an important characteristic of princess stones because lower-quality color is more visible at the stone's corners.
Round: Traditional solitaire engagement rings have remained the most popular choice for many couples over the decades, and most involve round diamonds. Round diamonds are incredibly versatile and can be found in prong and channel settings, with or without accent stones, and in a variety of unique engagement rings and bridal sets. 
Oval: The oval shape is frequently used with other stones in a detailed setting where it may be flanked by smaller diamonds, emeralds, sapphires, etc. Women with small fingers and hands sometimes choose this cut as a solitaire because it blends nicely with the length of a finger rather than standing out as a stronger focal point. 
Asscher: This pristine cut is a square with deeply trimmed edges. As a trademarked design, Asschers are rare and very sought-after for their remarkable depth and beauty. Couples interested in this unique shape should take care to choose only authorized dealers to guarantee a worthwhile purchase. 
Cushion: Gently rounded like a pillow or cushion, this smooth shape is reminiscent of vintage or antique designs. Cushion shapes are relatively rare and are often set off as solitaires rather than being incorporated into elaborate settings. Good luck choosing the right diamond for you! Everyone's style is different and you need to choose a diamond shape you like and that complements your finger! Remember Diamonds are a Girls Best Friend!
Pictures From: http://easydiamondguide.com/diamond-ring-shapes/
