Properties
| Category | Phyllosilicate |
|---|---|
| Formula | LiAlSi4O10 |
| Crystal system | Monoclinic |
| Color | Colorless, grey, yellow, pink, to white |
| Crystal habit | Tabular prismatic crystals and columnar masses |
| Cleavage | Perfect on {001}, poor on {201} with 38.5° angle between the two |
| Fracture | Subconchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 6–6.5 |
| Luster | Vitreous, pearly on cleavages |
| Streak | Colorless |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 2.4 |
From the Wikipedia article
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 it) is lower in iron than primary spodumene, making it a more useful source of lithium in, e.g., the production of glass. The colorless varieties are often used as gemstones.
Source
Source record: crystal-compendium/petalite/minerals.json. Fetched from English Wikipedia by the operator 2 October 2026.
https://en.wikipedia.org/wiki/Petalite — revision id 1335781030. Text and properties from Wikipedia, licensed CC BY-SA 4.0.