The extra expense is due to the fact that the treatment required to give the diamonds watch their blue color is costly. Obviously the cost of a necklace also depends on the cut, clarity and carat weight of the blue diamond or diamonds it has.Why They are Better Than Sapphire NecklacesYou may be wondering why one would bother purchasing a blue diamond necklace rather than one that contains sapphires given that the color is the same. There are actually three valid reasons for choosing a blue diamond necklace over one containing sapphires. First of all, sapphires cost a great deal more to purchase than synthetically enhanced blue diamonds.A blue diamond necklace will also have more sparkle, fire and brilliance than one that is made with sapphires. Added to that, blue diamonds are more durable and scratch proof than sapphires so they can be worn more often without fear of damage.If you love this article, you will also love another article written by this article author on diamond star necklace and diamond cross pendants.In the vast majority of cases any blue diamond necklace you find available for purchase at a fine watches retailer will be made out of gemstones that have been treated to give them their color. These diamonds my watches are originally gems with a yellow or brown tint, but the pigment is no longer visible after the color has been added.Diamonds chosen for this kind of treatment may not start out with the best color but they do have excellent clarity because any inclusions are more obvious in blue gemstones. A blue diamond necklace that has been enhanced costs as much if not more than one that has regular diamonds.