Your answer depends on why you are buying diamonds.
As an investment, you can educate yourself as to the four Cs of diamond value: cut, clarity, colour and carat weight, and then buy the highest grade diamond with the heaviest carat weight that you can afford.
As bling, you can forego everything above except carat weight and understand that the diamond is not an investment grade gem-stone and may not sell for as much as you paid for it.
As industrial hardner, you can look for the size, grade and quantity that you want to buy.
Uncut unshaped diamonds look like shiny black coal
Black diamonds are diamonds, but they are black, and not transparent. Follow the link, below, to see photos of black diamonds.
You can pick up diamonds from the earth at the Crater of Diamonds State Park in Arkansas.
Rihanna sung diamonds and if you look up " !yt Rihanna Diamonds " then you will be sent to YouTube and your search "Rihanna Diamonds" will be there
Faceted, finished brown diamonds are simply diamonds within that colour range. Chocolate diamonds are an intense brown colour.
You can review the link, below, to look at images of natural diamonds.
Yes, some diamonds will give this appearance.
Jewelery can contain real diamonds, and jewelery can contain other gems, including stones meant to look like diamonds.
I think it would be best if you have a professional look at your diamonds. They will probably charge a fee.
You can learn more about diamonds and their visual dazzle, below.
yes black diamonds are rare in this region
look in mineshafts