Large particles are not typically formed on intrusive rocks. In fact, intrusive rocks, which cool slowly underground, are characterized by their large crystals, also known as phaneritic texture. This is because the slow cooling process allows ample time for mineral crystals to grow larger.

Here's why:

* Slow Cooling: Intrusive rocks cool much slower than extrusive rocks, which erupt onto the surface. The Earth's crust provides a much more insulated environment, allowing for slow and gradual heat loss.

* Crystal Growth: Slow cooling allows atoms in the molten rock to move around more slowly and arrange themselves into larger, more organized crystal structures.

* Large Crystals: The result of this slow growth process is large, visible crystals, often referred to as phenocrysts. These crystals are easily discernible to the naked eye and are a hallmark of intrusive rocks.

Examples of intrusive rocks with large crystals:

* Granite: Known for its large, easily visible crystals of quartz, feldspar, and mica.

* Gabbro: A dark-colored intrusive rock with large crystals of plagioclase feldspar and pyroxene.

* Diorite: An intermediate-colored intrusive rock with large crystals of plagioclase feldspar and hornblende.

In contrast, extrusive rocks, which cool rapidly at the surface, typically have smaller crystals or even a glassy texture (no visible crystals). This is because the rapid cooling process does not allow for the formation of large crystals.

Therefore, the presence of large particles is not a characteristic of intrusive rocks, but rather a result of their slow cooling process, leading to the formation of large crystals.