Diamonds are indeed just crystalline carbon (charcoal is another form of carbon as is graphite (e.g. pencil lead)). Unfortunately, carbon only crystalizes at tremendous pressures and high temperatures. General Electric has been making synthetic diamonds for several years for industrial uses (cutting tools and others). In their process, carbon is compressed in a hot press to several dozen tons per square inch while being heated to a few thousand degrees. (The rams in such presses need to be made from graphite as well -- any metal would melt). There is apparently more to the trick -- and G.E. isn't telling. However, recently, some researchers at Varian found a way to make thin coatings of diamond at low pressures by carefully regulating a flame... The process has been used to make diamond coatings for glass and even plastics.

A short description of the manufacture of diamonds can be found at:

http://www.elwood.com/diam2.htm

What is the difference betweenwater and Ice ???

The chemical composition of BOTH liquid water and solid Ice is H2O. This means that there are two atoms of Hydrogen (H) and one of oxygen (O). So the composition of water and ICE are the SAME. So why are they so different??? After all, water flows all over the place and ice is a solid like a piece of rock!!!
Well, the difference is in how the molecules of H2O are arranged!! In liquid water the water molecules are randomly arranged...this is because in a liquid there is no LONG RANGE structure...but in ICE the H2O molecules are all arranged in a fixed and definite way.

So here is an excercise that is A LOT OF FUN and maybe,just maybe, you can get your teacher to allow your whole class to do this try this.

Let's say there are 20 students in your class.....have everyone line up according to this: 5 rows of 4 students each...now we can simulate a solid(ice) a liquid (water) and even a gas !!!

to make ice: each student has to stand at a FIXED spot and not move their feet. everyone has to be lined up and there has to be a perfect pattern..like soldiers lining up to march.

to make a liquid: each student starts at the same position as when they were in the ice pattern but now a student can move their feet by 10 inches only...that is they can move around in a small area.

to simulate a gas: each student can move in any direction they want and keep moving that way until they bump into another student (your teacher may not like this idea!!) or when they hit the boundaries of the simulation region(mark with chalk or string )

Now WHAT DOES THIS HAVE TO DO WITH DIAMOND ????

Well, diamond is made up of the element CARBON. And just like ice and water and steam, CARBON COMES IN DIFFERENT FORMS.

One form that is stable at room pressure is CHARCOAL!!!! yep just like the stuff your mom or dad uses to make a BBQ !!!!!!!

But if you take that charcoal and squeeze it to 15000 times the pressure of the atmosphere, then the CHARCOAL TRANSFORMS TO DIAMOND. This is because the ARRANGEMENT of the carbon atoms changes from a loose packing of carbon atoms to a dense packing of carbon. When the packing of the carbon changes, the properties of the material changes from that of charcoal to that of DIAMOND!!!

In the earth the pressure goes up as the depth increases...finally at about 80 miles depth, the pressure is high enough to transform tiny bits of charcoal (geologists call it graphite) to diamond.

you can look up more info on minerals and diamond at:

http://www.minerals.net/glossary/glossary.htm

GOOD LUCK!

Diamonds are made out of pure carbon, just like graphite, but the atoms of carbon in a diamond are bonded to each other differently from the way they are in graphite. The rearrangement of the bonds occurs under very high pressure, like what you would find over 60 miles underneath the surface of the earth. Some tiny tiny diamonds are made in metamorphic rock that forms where one plate gets subducted underneath another. How such rocks get back up to the surface of the earth from over 60 miles deep is a very good question, and geologists are still working on it.

Here is a question for you: What layer of the earth are diamonds formed in if they form 60 miles deep?

Here is the reference for an article that might help:
Trautman, Griffon, and Scharf, "Microdiamonds," Scientific American, Aug,1998, pp. 82-87.

Good luck!