Reference

Common minerals in crustal rocks like granite that can generate hydrogen include:

1. Feldspar: A group of framework silicates that make up a significant portion of the Earth's crust. They are found in igneous rocks such as granite, rhyolite, and basalt.
2. Quartz: A very common mineral composed of silicon and oxygen, often found in granite and other igneous rocks.
3. Mica: A group of complex silicates that include biotite and muscovite, which are common in granite and can contribute to hydrogen generation.
4. Amphiboles: A group of complex silicate minerals that can also be present in granite and might be involved in hydrogen generation.
5. Olivine: Although not as common in granite, it is a green mineral that can generate hydrogen when altered to serpentine.

The process of hydrogen generation in these rocks is often linked to the oxidation of ferrous iron to ferric iron in the presence of water. Crushing experiments conducted on rocks like granite, andesite, and labradorite have demonstrated hydrogen diffusion from these materials. Quartz and feldspar, being the most abundant minerals in granite, are likely the primary contributors to hydrogen generation in these rocks. For more detailed information, you can refer to scientific articles such as "Hydrogen generation during hydrothermal alteration of peralkaline granites" ScienceDirect and "Hydrogen in rocks: an energy source for deep microbial communities" PubMed.