What does pneumatolysis involve?

Pneumatolysis refers specifically to the process of crystallization of minerals from gaseous sources. This geological phenomenon occurs when hot gases, often rich in volatile substances like water vapor, carbon dioxide, and other elements, interact with rocks or minerals. As these gases cool and react chemically with the surrounding material, they can lead to the formation of new mineral species through the precipitation of elements within the gas phase.

In contrast to the other processes mentioned, pneumatolysis is distinct because it emphasizes the role of gas rather than other states of matter. Crystallization from a solid source relates more to processes like sedimentation or metamorphism, while the creation of minerals from liquid magma is more about magmatic processes and crystallization from molten rock. The decomposition of minerals in the earth's crust generally refers to weathering or alteration processes, which do not align with the definition of pneumatolysis focused on gas interactions.

Understanding pneumatolysis is essential in mineralogy and petrology as it highlights the diverse environmental conditions under which mineral formation can occur.