# Tonstein

> hard, compact sedimentary rock that is composed mainly of kaolinite or, less commonly, other clay minerals

**Wikidata**: [Q9394820](https://www.wikidata.org/wiki/Q9394820)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Tonstein)  
**Source**: https://4ort.xyz/entity/tonstein