Question

In the ASCE or USBR Rock Weathering Descriptors, the description of "Moderately Severe" says that all (minerals) except quartz are discolored or stained, and that all feldspars are dull, discolored and turning to clay. Why is the quartz not discolored or stained while the feldspars are? Quartz weathers faster than feldspars Physical weathering affects feldspars more than quartz The feldspars are less resistant to weathering than quartz Feldspars tend to be more colorful than quartz, which is usually clear

Answer 1

Quartz is a mineral compound consisting of silicon and oxygen atoms whereas Feldspar is a mineral compound consisting of aluminium, silicon and oxygen atoms.

In the ASCE or USBR Rock Weathering Descriptors,the description of "Moderately Severe" says that all (minerals)except quartz are discolored or stained, and that all feldspars are dull, discolored and turning to clay.

Quartz are not discolored or stained while the feldspars are because physical weathering affects feldspars more than quartz.