Why does magma form rocks with different depths and different surfaces?

Simply put, different magma crystallization environments lead to different rocks. As we all know, magma is a high-temperature, hot, viscous and volatile silicate melt produced in the deep crust or upper mantle. To form rocks, it is necessary to go through complex processes such as cooling, depressurization and volatilization. Due to the slow decrease of temperature and pressure, the crystallization process of intrusive rocks formed in deep places is slow, and rocks with very good crystallinity can be formed, such as granite (acidic), diorite (neutral), gabbro (basic) and peridotite (ultrabasic). The crystallization environment in shallow place is worse than that in deep place, and the surface layer is the worst (that is, extrusive rock), such as rhyolite and dacite (acidic), andesite (neutral), basalt (basic) and picrite (ultrabasic); The worst crystallization environment is in water. Magma cools rapidly to form glassy rocks, such as biotite, which looks like asphalt and is completely composed of vitreous.

In fact, this is just a superficial answer. There are many other factors, such as cooling time. I hope I can help you!