You can buy black diamond loose stones online but you would have to do an extensive search to find then at a jewelers in your city. They are quite rare, especially when loose.
Black diamonds, also known as carbonado, are found in Brazil among many other places. They are usually used in diamond drills and their texture varies considerably from being porous to very compact. Black diamonds can be polished up very nicely however and have become quite popular over the past few years. They are sometimes featured with white diamonds in a contrasting effect that can then be quite striking and attractive.
When buying black diamond loose stones online there are some points to keep in mind.
Ensure that the dealer is a bona fide dealer. How long has the dealer been on site? Is there a fixed address and contactable phone and fax numbers? Can you ring and talk to someone who knows about black diamonds and
You need to be very careful with black diamonds when buying them. They should be valued properly by an independent appraisers and a certificate of authenticity issued. One cannot emphasis this enough. Black diamonds are far more difficult to perceive as being a diamond than the usual.
Black diamond loose stones have the potential of a good future investment so it might even be worth while getting some good quality loose ones and keeping them.