The Earth's mantle is primarily composed of ultramafic rocks, which are characterized by their high content of magnesium and iron. The most common minerals in these rocks are:

* Olivine: A silicate mineral rich in magnesium and iron, and is the dominant mineral in the upper mantle.

* Pyroxene: A silicate mineral also rich in magnesium and iron, found in both the upper and lower mantle.

* Garnet: A silicate mineral that contains various elements like magnesium, iron, calcium, and aluminum. It's more common in the lower mantle.

While olivine and pyroxene are the dominant minerals, the mantle also contains smaller amounts of other minerals like:

* Spinel: A mineral with magnesium, aluminum, and oxygen, found in the transition zone between the upper and lower mantle.

* Perovskite: A mineral with magnesium, silicon, and oxygen, found in the lower mantle.

It's important to note that the composition of the mantle changes with depth. The upper mantle is primarily composed of peridotite, a rock rich in olivine and pyroxene. As you go deeper, the pressure and temperature increase, leading to changes in the mineral composition. The lower mantle is believed to be composed of denser minerals like bridgmanite and ferropericlase.

Here's a table summarizing the main mineral groups and their location in the mantle:

| Mineral Group | Location |

|---|---|

| Olivine | Upper Mantle |

| Pyroxene | Upper and Lower Mantle |

| Garnet | Lower Mantle |

| Spinel | Transition Zone |

| Perovskite | Lower Mantle |

Remember, the exact composition of the mantle is still being studied, and we continue to learn more about it through ongoing research.