The value of the 'stone' -- meteorite? -- probably depends on who wants to purchase it and how much the buyer is willing to pay for it.
The diamond value, especially of a 'black diamond' may not be as high as its 'from space' value.
This is not a large market, so you'll need to discover the market and then ask the question there.
Black diamonds, properly Carbonado, are priced a little less than clear diamonds of the same carat weight.Your local jeweler may be able to show you black diamonds with prices.
The value of the stone(s) depends on the cut, natural colour, carat weight and clarity of the stone. A gemologist who is expert in black diamonds can help you value the stone(s).
Today black diamonds are sold for prices that are comparable to those of white diamonds.
diamonds
By weight, diamonds are worth more because they are much more rare than gold.
A black diamond tattoo stands for uniqueness, and rarity. Black diamonds are very rare, and much different from traditional, regular diamonds.
It's worth whatever someone will pay you for it.You can take it to a pawn shop, or a jeweler and ask. Man-made diamonds are less expensive than natural diamonds.
Your ring -- lacking any documentation as to its metal and details about the diamonds -- is worth whatever someone will pay you for it. A local jeweler can help you understand the facts about your bracelet, and you can pay a gemologist to evaluate the diamonds.
The answer is unknowable, since not all the diamonds in the world have been mined to date.
5 dollars
Anything is 'worth' whatever someone will pay you for it. Miracle Diamonds, as below, is apparently a wholesaler of merchandise that includes diamonds. You can review their materials to determine what you want to purchase, and how much you will pay.
Because they look nice and are hard to get. It takes a lot of work to find and dig up diamonds in diamond mines.