1. Igneous Rocks:

* Formation: Formed from the cooling and solidification of magma (molten rock) or lava (magma that has erupted onto the Earth's surface).

* Types:

* Intrusive igneous rocks: Formed when magma cools and solidifies beneath the Earth's surface. They have larger crystals due to slower cooling. Examples: granite, gabbro.

* Extrusive igneous rocks: Formed when lava cools and solidifies on the Earth's surface. They have smaller crystals due to faster cooling. Examples: basalt, rhyolite.

2. Sedimentary Rocks:

* Formation: Formed from the accumulation and cementation of sediments (rock fragments, mineral grains, and organic matter) that have been transported and deposited by wind, water, or ice.

* Types:

* Clastic sedimentary rocks: Formed from fragments of other rocks. Examples: sandstone, shale, conglomerate.

* Chemical sedimentary rocks: Formed by the precipitation of minerals from a solution. Examples: limestone, rock salt, gypsum.

* Organic sedimentary rocks: Formed from the accumulation and decomposition of organic matter. Examples: coal, oil shale.

3. Metamorphic Rocks:

* Formation: Formed when existing rocks (igneous, sedimentary, or other metamorphic rocks) are subjected to intense heat and pressure. This causes changes in their mineral composition, texture, and structure.

* Types:

* Foliated metamorphic rocks: Rocks with a layered or banded appearance due to the alignment of minerals under pressure. Examples: slate, schist, gneiss.

* Non-foliated metamorphic rocks: Rocks that lack a layered appearance. Examples: marble, quartzite.

Remember that the rock cycle is a continuous process, and rocks can transform from one type to another over geological time.