Diamond facts...
Cullinan at 3,106 carats.
-What is the hardest natural substance on Earth?
The Diamond.
-80% of the world's diamonds are not suitable for Jewelry.
-Is a Diamond Indestructible?
No. The fact that Diamonds are a hard substance refers to their ability to withstand scratching. But that is different than toughness, which refers to the ability to withstand breaking or cleavage.
-How old are most diamonds which are found in nature?
1 billion to 3 billion years, by most accounts.
-How do diamonds reach us?
They are formed deep within the Earth's crust, and come to the surface via Volcanoes. Most diamonds are found in Kimberlite, which is volcanic rock.