If you heat a diamond to about 763° Celsius (1405° Fahrenheit), it will turn to vapor.
 
At normal temperatures and normal pressure, a diamond is hard as a rock. In fact, diamonds are some of the hardest rocks on Earth. At normal atmospheric pressure, diamonds will not evaporate at all.
 
If diamonds are too tough to evaporate, how do they turn to vapor?
 
They oxidize. Oxidation describes a chemical reaction in which oxygen interacts with other substances. Oxygen is a major part of our atmosphere, and substances oxidize all around us, all the time. Rust, for instance, is an example of the oxidation of iron. Rust is also known as iron oxide.
 
Diamonds are a form of pure carbon. As carbon oxidizes, the chemical reaction forms the everyday gases carbon dioxide and carbon monoxide. These are the vapors that a diamond becomes at such high temperatures.
  • In non-oxidizing conditions under normal pressure, diamonds can be heated to about 1,900° Celsius (3,452° Fahrenheit) before changing their crystal structure.
  • In non-oxidizing conditions at extremely high pressure (197,385 atmospheres), diamonds can withstand temperatures of up to 3,500° Celsius (6,332° Fahrenheit) before changing their crystal structure.
  • In the absence of oxygen, diamonds can be heated to much higher temperatures. Above the temperatures listed below, diamond crystals transform into graphite. The ultimate melting point of diamond is about 4,027° Celsius (7,280° Fahrenheit). 
atmosphere
Noun

layers of gases surrounding a planet or other celestial body.
atmospheric pressure
Noun

force per unit area exerted by the mass of the atmosphere as gravity pulls it to Earth.
chemical reaction
Noun

process that involves a change in atoms, ions, or molecules of the substances (reagents) involved.
diamond
Noun

type of crystal that is pure carbon and the hardest known natural substance.
evaporate
Verb

to change from a liquid to a gas or vapor.
gas
Noun

state of matter with no fixed shape that will fill any container uniformly. Gas molecules are in constant, random motion.
oxidize
Verb

to combine with oxygen to form a different compound (oxide).
pressure
Noun

force pressed on an object by another object or condition, such as gravity.
rust
Noun

red or orange coating that forms on the surface of iron when it is exposed to oxygen and moisture. Also called iron oxide or ferric oxide.
temperature
Noun

degree of hotness or coldness measured by a thermometer with a numerical scale.
vapor
Noun

visible liquid suspended in the air, such as fog.
vaporize
Verb

to turn into gas, or vapor.

Articles & Profiles

Worksheets & Handouts

Websites

  • Credits

    Media Credits

    The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

    Writer

    Caryl-Sue, National Geographic Society

    Editor

    Melissa MacPhee, National Geographic Society

    Producer

    Caryl-Sue, National Geographic Society

    Last Updated

    Nov. 4, 2015

  • User Permissions

    For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

    Media

    If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

    Text

    Text on this page is printable and can be used according to our Terms of Service.

    Interactives

    Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.