In nature, black mica is a solid. Sulfuric acid is used to transform black mica (aka. biotite) into a liquid form (ie. Adya Clarity). Once black mica is in a liquid form, it can thoroughly mix with water, bind with contaminants and pull them out of the water.
After Adya Clarity is diluted further in water, the concentration of sulfuric acid is 0.0005% (28 times less than what is found in alcoholic beverages).
As approved by Health Canada (Natural Health Product #: 80028256), it is also used to improve the extraction yield of coffee solids.
https://health-products.canada.ca/lnhpd-bdpsnh/info.do?licence=80028256
As approved by the FDA, sulfuric acid is used in the manufacture and modified hop (a type of plant) extract in beer.