No one knows about diamonds that are not unearthed: their size, quality or location.
To date, however, the largest raw diamond found by mankind was found in 1906, and it weighed just over 3,000 carats. It fit into the palm of an adult male's hand. There have been no other diamonds of this size found since.
No, diamonds don't surround the earth's mantle. Diamonds are formed within the earth's mantle, and are rare.
The earth is mined to get diamonds.
Diamonds are formed deep within the earth's mantle.
Diamonds can be found on every continent on Earth, except Europe and Antarctica.
Diamonds have to be mined by humans
Natural diamonds that erupt to the earth's surface were formed with the earth. Diamonds that come to earth from space may have been formed before earth: that research hasn't been documented to date.
There is an estimated total of about 1,200,000,000,000 carats of diamonds on Earth, which is roughly equivalent to 240,000 metric tons. Most of these diamonds are located deep within the Earth's mantle and are not easily accessible.
All diamonds are erupted to the surface of the earth from deep within the mantle, where diamonds are formed. Diamonds are mined on every continent on earth except Europe and Antarctica.
Diamonds are erupted to the surface of the earth by volcanic pipes.
All diamonds are found in the earth.
Generally, diamonds are formed in the Earth and not from Supernovas.
If I remember right from Earth Science, it is because diamonds are the strongest known gem on Earth.