Clear quartz is mostly used in energy work. It has no specific associations, but can intensify and regulate energy. Similar to selenite, it can be used in cleansing because of this. Due to this, it can also be used to replace any other crystal in a ritual. It is often used as a "filler" crystal in these instances.
“Clear Quartz,” Digital Collections - Lake Forest College, accessed July 2, 2022, http://collections.lakeforest.edu/items/show/6953.