However, it's important to know that carbon can exist in different forms, each with different properties. Here are the most common:

* Diamond: The hardest known natural material, solid.

* Graphite: A soft, slippery material used in pencils, solid.

* Fullerene: A molecule with a spherical or cage-like structure, solid.

* Carbon nanotubes: Cylindrical structures with exceptional strength and electrical conductivity, solid.

While carbon is generally a solid, it can become a gas under extreme heat (over 4000°C). This is why we see carbon dioxide in the atmosphere, which is a gas.