Mineral Of The Day #115: Pyrophyllite
Mohs Hardness Scale: 1.5-2
Category: Phyllosilicate mineral
- Pyrophyllite’s name comes from the Greek pyros (fire) and phyllos (a leaf).
- It has a pronounced pearly lustre.
- The compact variety of pyrophyllite is used for slate pencils and tailors chalk, and is carved by the Chinese into small ornaments.
- Because it has excellent thermal stability, it is added to clay to reduce thermal expansion when firing.
- It is also used as an insecticide and for making bricks.