In granite, the predominant phase of quartz present is typically α-quartz. β-quartz is relatively rare in granite and is more frequently found in specific types of metamorphic rocks. The α-quartz in granite is a stable form of quartz that contributes to the overall composition and structure of the rock.

β-quartz is typically not found in granite in nature. β-quartz, unlike α-quartz, is only stable at high pressures and temperatures (between 573°C and 870°C). When temperatures fall below 573°C, β-quartz usually reverts to α-quartz. Granite forms under conditions that favor the formation of α-quartz, which is stable at the relatively low temperatures and pressures beneath the Earth's surface where granite typically forms. Therefore, you'd primarily observe α-quartz in granite.

β-quartz, unlike α-quartz, is a high-temperature polymorph of quartz and is typically found within rocks that form in high-temperature conditions such as certain types of volcanic or metam rocks. However, it's important to note that you rarely find β-quartz in rocks at the Earth's surface.

This is because β-quartz is stable at temperatures between approximately 573 and 870°C. Under normal atmospheric pressure, as the temperature decreases, β-quartz transforms back into α-quartz, the more common and stable form at lower temperatures.

So in the natural environment, β-quartz is most likely to be found within the Earth's crust in regions with high temperatures, such as around magmatic bodies or within the mantle. In surface rocks, any original β-quartz would likely have transformed into α-quartz as the rock cooled. For practical purposes, one would more likely encounter β-quartz in a laboratory setting where the necessary high-temperature conditions can be maintained.

If β-quartz in granite transforms to α-quartz, it would likely result in changes to the physical and chemical properties of the rock. Here are some possible effects:

1. Changes in mineral assemblage: α-quartz is the most common form of quartz found in igneous rocks, including granite. As β-quartz transforms to α-quartz, the mineral assemblage of the granite may change, potentially altering its geochemical characteristics.
2. Crystal structure: β-quartz has a distinct crystal structure compared to α-quartz. When β-quartz transforms to α-quartz, the crystal structure of the quartz in the granite may change, which could affect its optical properties and other characteristics.
3. Mechanical properties: The transformation β-quartz to α-quartz may not significantly affect the overall mechanical properties of the granite, but any changes could potentially affect its strength, hardness, and durability.
4. Metamorphic phenomena: In some cases, the transformation of β-quartz to α-quartz may be accompanied by metamorphic phenomena, such as changes in mineral composition, texture, or cation exchange. These changes could result in the formation of new minerals or the recrystallization of existing minerals.
5. Tectonic implications: The transformation of β-quartz to α-quartz may have implications for the tectonic evolution of the granite body. For example, if the granite formed in a high-temperature environment and subsequently underwent metamorphism, the changes in the quartz structure could provide clues about the tectonic history of the area.

It is essential to note that the transformation of β-quartz to α-quartz is a complex process that depends on various factors, including temperature, pressure, and the presence of other minerals. In natural settings, these changes occur gradually over time, often over millions of years.