Here's why:

* Hardness: Quartz is a very hard mineral, ranking 7 on the Mohs Hardness Scale. This means it can scratch most other materials, including dirt, grime, and stains.

* Abrasive properties: Quartz's hardness allows it to create a rough surface that can physically remove these unwanted substances from surfaces.

When ground into fine particles, quartz becomes an effective abrasive agent in scouring powders. It provides the necessary scrubbing power to clean pots, pans, and other surfaces without causing excessive damage.

However, it's important to note that while quartz is a common ingredient, some scouring powders also use other abrasive materials like feldspar or pumice.