* Compound: Tin is found in compounds in the Earth's crust. The most common ore of tin is cassiterite (SnO2), which is a compound of tin and oxygen.

* Pure Element: Tin can also be found as a pure element, though it is much less common. This is primarily in the form of native tin, which is a relatively rare mineral.

So, while tin is most often found in compounds, it does exist in its pure form as well, albeit less frequently.