The most common type of Diamond Necklace is a single diamond set in a 14k gold basket mounting that hangs on a simple chain. In the jewelry industry this is known as a Diamond Solitaire Pendant. For the readers of this article, our buying advice is aimed mainly at this type of single diamond pendant, or necklace.
1. How to choose the right diamond size: most people can not visualize diamonds by weight, so here is a handy starting point. A 1 Carat diamond is the same diameter as the flat top of a standard pencil eraser, a little over 1/4-inch or 6.5mm. Worn on a choker length chain, this size diamond will command attention and convey status upon the woman that owns it. Depending upon the diamond quality a 1 carat pendant will cost from about $1,200 to $5,000.
For those of us on a budget the good news is that almost any size diamond can look beautiful and appropriate when worn as a necklace. There are a few basic guidelines that you should consider before you purchase. For example, a 1/4-carat diamond will look precious and correct on the neck of a woman 24 years old or younger. A 1/2 to 3/4-carat diamond is appropriate for a woman up to her late 30’s, especially if she is a petite size.
Consider the character and style of the woman as well when choosing your diamond size. The fashion minimalist woman who wears simple black or white clothing, as well as the tailored woman, can wear a smaller diamond. On the other hand, for the extrovert woman who wears layers of vivid colors, the smaller diamond simply will not look correct.
2. How to judge diamond cost versus quality: the cost of your diamond will be determined by what is commonly called The Four C’s: Color, Clarity, Cut and Carat weight as measured on the GIA rating scale. While there is much to be read on these characteristics, the following is a very brief guideline that will result in a beautiful diamond at the lowest cost.
For diamond Color, the best value is G-H-I. The higher grade colors (D-E-F) will cost you up to twice as much, and the average person will not perceive a noticeable difference. The lower color grades (J-K and below) will exhibit a definite dirty-yellow cast.
For diamond Clarity, any diamond rated SI or higher is considered “eye clean”. This means that you don’t need to invest in a VS or higher Clarity diamond because the difference can only be discerned under 10-power magnification. The best value is often an I1 Clarity diamond with minute white crystal inclusions. The cost difference between an I1 Clarity grade and a VVS Clarity grade can be as much as 400%. Although bargain prices can be found on the lowest Clarity grades of I2 and I3, the majority of diamonds in this grade will appear either dark or very dull and cloudy.
For diamond Cut, choose either Excellent or Very Good grades. The hand of the Cutter is what breathes life, fire and a shower of scintillating colors into a diamond. No matter what the other characteristics are, a Poor Cut diamond will appear dull and lifeless. At the end of this article, you will find a link to a single page that compares prices of 48 different quality and carat weights of diamond solitaire pendants.
3. How to choose the right style and length of necklace chain: the chain most commonly sold with a diamond solitaire necklace is an 18-inch.5mm link chain. Most retail jewelers choose to sell it because it lowers their cost. Unfortunately this is a poor choice since it will easily break and 18 inches may be too short depending on the woman who wears it.
In terms of chain width and style, the better choices are a 1 to 1.75mm twisted rope, or a 1 to 1.5mm box link chain. Perhaps the most elegant choice is a 1 to 2mm round snake chain. These chains are well worth the difference in price since they both enhance the look of your necklace, and they will secure the diamond safely on your neck. Don’t accept a standard lightweight link chain because sooner or later it will break and you will lose your diamond.
In length, a solitaire diamond should always be set on a “choker” chain which would be between 18 and 23 inches long. The neckline of a woman will depend on her body shape and size, and the chain should match. Here is a simple rule for determining your chain length: the diamond should rest in or just below the small depression of skin between the collarbones. For many women a common 18-inch chain will place the diamond on their thyroid cartilage, and this is too short. You can use a string or thread to measure this length before you buy your chain.