Mineralpedia Details for Dawsonite
Dawsonite
John William Dawson is the namesake of Dawsonite as a former Canadian geologist and Principal of McGill University in Montreal, Canada. Dawsonite is an uncommon mineral that occurs in localities in Canada, the United States, Italy, Switzerland, Albania, Hungary, Russia, Tanzania, Algeria, Australia, and a few others. In its Canadian locality is occurs as a coating on vug walls and fractures in hydrothermally altered feldspathic dikes and hornfels, in its US locality in the Green River formation as an authigenic mineral in alkaline shales and coal bearing rocks, and at its Tanzanian locality in saline soil in nepheline syenite tuff.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/dawsonite.pdf
- Formula
- NaAlCO3(OH)2
- Crystal System
- Orthorhombic
- Crystal Habit
- Radial, Acicular, Encrustations
- Cleavage
- Perfect, None, None
- Luster
- Vitreous - Silky
- Color
- colorless, white
- Streak
- white
- Class
- Orthorhombic - Dipyramidal
- Fracture
- Uneven
- Hardness
- 3
- WebMineral
- View Dawsonite
- Mindat
- View Dawsonite
Dawsonite from Amiata Mt., Tuscany, Italy
Snow white acicular radial sprays to 1mm.
Dawsonite from Oued Sidi Bou Ali, Tenes, Algeria
White radial flat-lying crystal groups of Dawsonite to 0.5mm across.
Dawsonite from Francon quarry, Montreal, Quebec, Canada
- Special Info
- Type Locality
Exceptionally large, and well-formed prismatic crystals with terminations in groups to 5mm. The crystal size is more like 2-3mm. The long bladed, creamy brown crystals are Celestine.
Dawsonite from Komana, Drin valley, Shkodra Co., Albania
Snow white, almost fibrous, Dawsonite crystals, in groups to 8mm.
Dawsonite from Limoncino, Livorno, Livorno Prov., Tuscany, Italy
Excellent white sprays to 1mm.
