Petalite
| Colour | White, Clear, Pink, Gray, Yellow |
|---|---|
| Mohs hardness | 6–6.5 |
| Lustre | Vitreous, pearly on cleavages |
| Streak | Colorless |
| Crystal system | Monoclinic |
| Transparency | Transparent to translucent |
| Cleavage | Perfect on {001}, poor on {201} with 38.5° angle between the two |
| Fracture | Subconchoidal |
| Chemical formula | LiAlSi 4 O 10 |
| Specific gravity | 2.4 |
What is Petalite?
Petalite, also known as castorite, is a lithium aluminum phyllosilicate mineral LiAlSi4O10, crystallizing in the monoclinic system. Petalite occurs as colorless, pink, grey, yellow, yellow grey, to white tabular crystals and columnar masses. It occurs in lithium-bearing pegmatites with spodumene, lepidolite, and tourmaline. Petalite is an important ore of lithium, and is converted to spodumene and quartz by heating to ~500 °C and under 3 kbar of pressure in the presence of a dense hydrous alkali borosilicate fluid with a minor carbonate component. Petalite (and secondary spodumene formed from
How to identify Petalite
- Lustre: Vitreous, pearly on cleavages.
- Hardness: Mohs 6–6.5 — about as hard as a steel knife.
- Streak: Colorless.
- Habit: Monoclinic crystal system.
Petalite in different forms
Stones often confused with Petalite
Frequently asked questions
How hard is Petalite?
Petalite is Mohs 6–6.5 on the hardness scale.
What colour is Petalite?
Petalite is typically white, clear, pink, gray, yellow (Colorless, grey, yellow, pink, to white).