Can diamond be flammable under the right conditions?

Consider that coal is mostly carbon. When you put it in an oxygen rich environment and apply a little heat, the carbon reacts with the oxygen and gives off more heat and sets off a chain reaction. The carbon and oxygen become carbon dioxide and carbon monoxide (any others?).
Graphite is, from what I understand, sheets of carbon and diamond is carbon arranged in little cubes and neither, to my knowledge is flammable.
What if I put both in a high pressure, pure oxygen chamber and applied some sort of extreme heat to them. Can I get either the graphite or the diamond to ignite and continue to burn on its own?

Yup. That’s how they figured out diamonds were carbon originally.

Heat the diamond with a blowtorch and drop it in liquid oxygen and it will burn on its own, no problem.

Yes. Diamonds can burn, though they have a high ignition point.

Ask and ye shall receive.

Isn’t the carbon in coal mostly in the form of graphite?

accidently and without the liquid oxygen. I was trying to clean a diamond film that had some contamination on it. I tried everything and couldn’t get it to clean up. So I had the bright idea of burning the contamination off…when I was done the contamination and diamond film was gone.

I’m always amazed how many time my experience with diamond is relevant here. Every few months someone is asking about it in some way.

Wow. What and interesting question, and interesting link. I had no idea. Never thought of it really.

And I thought that lighting cigars with hundred dollar bills was expensive. Diamonds in champagne glasses full of liquid oxygen. Now that’s a candle.

graphite is the highest grade coal though doesn’t burn well. fuel coals are lower grades of anthracite, bituminous and lignite.

… and let’s not forget that the first person to burn a diamond (intentionally or otherwise) was Antoine Lavoisier, back in the eighteenth century.

No, no, no!

Graphite is not coal. Coal has no graphite.

Diamond and Graphite both have a crystalline structure. In diamond, each carbon atom is coordianted by four others (tetrahedral coordination), which manifests itself macroscopically as an isometric crystal usually in a cubic or octahedral form. In graphite, each carbon atom is coordinated by three others (triangular coordination), which results in hexagonal crystals that form “sheets” which are weakly bonded to other “sheets”.

Coal may be mostly carbon, but it is not crystalline and contains no graphite. Graphite is not coal, much less the “highest grade”. (I’m not very well versed in organic geochemistry, so I can’t tell you exactly what it is without looking it up, but I know what it ain’t!)

“Diamonds are until they get heated up and dropped into liquid oxygen.”

**Yossarian ** says:

According to Wikipedia, coal can contain graphite:

If I recall correctly, physicist Phillip Morrison had a PBS special some years back, and he got Julia Childs (it was quite a few years back) to cook a diamond to ashes. So, yes, they will burn.

Well, if Wikipedia says so, who am I to argue?

I was under the impression pretty much everything can burn under the right conditions. Even water.

Burning water would be about as easy as burning carbon dioxide.

It’s not just Wikipedia – Google “Coal Graphite” and you’ll get lots of hits, many from respectable sources equating the two.

Certainly not all coal is graphite (which generally contains lots of much more complex hydrocarbons), but, apparently, in some circles, all graphite is a sort of “limiting case” of coal.
I brought up the Wikipedia page because, oddly enough, I’d been reading it last week, and the bit about graphite being the “pure case” of coal stuck in my mind. It’s not because I think Wikipedia is the Ultimate Reference Tool.

You can’t burn diamond “to ashes”. Ashes are from trace components in whatever you’re burning that either don’t burn, or burn to a solid. But diamonds are about as pure carbon as you’ll ever find, and carbon burns to a gas.

True. In both cases, you just need a stronger oxidizer than oxygen. Fluorine does the trick, and will quite energetically replace the oxygen in just about anything. You don’t want to be anywhere near when it happens though – byproducts of fluorine gas and water include HF, which happens to be once of nastier acids.

Of course, once you have your fluorinated combustion products, you’ve reached the end point, since there’s nothing that’s even more reactive.

If you stretch the definition of “burning” a bit, then you could also oxidize those fluorine compounds further, at the cost of putting in more energy than you’re getting back out.