Here's why:
* Sandstone Formation: Sandstone forms from the accumulation and cementation of sand grains. These sand grains can be composed of various minerals, including quartz, feldspar, mica, and rock fragments.
* Feldspar Abundance: The amount of feldspar in sandstone depends on the source rock from which the sand originated. If the source rock was rich in feldspar (like granite or gneiss), then the sandstone will likely have a higher proportion of feldspar.
* Weathering: Feldspar is less resistant to weathering than quartz. As rocks break down, feldspar tends to decompose faster, leaving behind quartz-rich sand. This means that sandstones derived from older, more weathered rocks will generally have less feldspar.
Therefore, while sandstone can contain feldspar, its presence and abundance vary greatly depending on the source rock and weathering history.
