1. Oceanic Crust:

* Composition: Primarily composed of basalt, a dark-colored, fine-grained igneous rock rich in magnesium and iron. It also contains gabbro, a coarser-grained version of basalt.

* Density: Denser than continental crust, around 2.9 g/cm³.

* Thickness: Relatively thin, averaging about 7 kilometers (4.3 miles).

* Age: Younger than continental crust, typically less than 200 million years old.

* Location: Found beneath the oceans, forming the ocean floor.

2. Continental Crust:

* Composition: More diverse than oceanic crust and includes a wider range of rocks, such as granite, sedimentary rocks, and metamorphic rocks. Granite, a light-colored, coarse-grained igneous rock rich in silica and aluminum, is a common component.

* Density: Less dense than oceanic crust, around 2.7 g/cm³.

* Thickness: Much thicker than oceanic crust, averaging about 35 kilometers (22 miles) but can reach up to 70 kilometers (43 miles) in some mountainous regions.

* Age: Older than oceanic crust, with some portions dating back billions of years.

* Location: Forms the continents and continental shelves.

Key Differences:

* Composition: Oceanic crust is mainly basaltic, while continental crust is more diverse, including granite.

* Density: Oceanic crust is denser, while continental crust is less dense.

* Thickness: Oceanic crust is thinner, while continental crust is thicker.

* Age: Oceanic crust is younger, while continental crust is older.

These differences have important implications for plate tectonics, as the denser oceanic crust subducts (sinks) beneath the less dense continental crust at convergent plate boundaries.