Re: Is diamond an element or a compound? Is it homogeneous or hetereogenous?

A diamond is considered a network covalent solid.  Atoms of the element 
carbon are linked together by a network of electron pair bonds extending 
throughout the entire crystal in what is called a network covalent solid.  
In effect, a crystal of such a substance can be regarded as a giant 
molecule.

Diamonds are not considered homogenous or heterogenous although they are a 
form of the element carbon.

Each carbon in diamond is bonded to 4 other carbons covalently.  Because 
covalent bonds are both strong and directed at specific angles, diamonds 
are hard and incompressible.

Other cool stuff I found out:  diamonds come from around 70 miles below 
Earth's surface within Earth's mantle.  They are made under enormous 
pressure about 55,000 atm!  (Sea level is considered 1 atm pressure.)  
They are created at temperatures of 1700-2300 degrees Fahrenheit.