Hureaulite Mineral Overview
- Mineral name: Hureaulite
- Mineral class: Phosphate
- Chemical formula: Mn₅(PO₃OH)₂(PO₄)₂·4H₂O (hydrated manganese phosphate)
- Crystal system: Monoclinic
- Mohs hardness: 4–5
- Color range: Pink, reddish-pink, brownish
- Luster: Vitreous
- Streak: White
- Cleavage: Good
- Fracture: Uneven
- Specific gravity: Approximately 3.1–3.2
- Transparency: Transparent to translucent
- Common locations: France, Portugal, United States, Brazil
- Uses: Collector mineral
- Similar minerals: Vivianite, ludlamite, eosphorite
Naming and Classification
Hureaulite is a hydrated manganese phosphate mineral, named after Hureau de Sénarmont, a French mineralogist.
It belongs to a group of secondary phosphate minerals that form in environments rich in manganese and phosphorus.
Physical and Optical Characteristics
Hureaulite typically occurs as:
- Prismatic to tabular crystals
- Radiating clusters
- Granular aggregates
Its color is most commonly:
- Pink to reddish-pink
- Sometimes brownish due to impurities
The luster is vitreous, giving crystals a bright, glassy appearance.
With a Mohs hardness of 4–5, it is moderately soft.
Color (Key Feature)
The pink coloration of hureaulite is due to:
- Manganese (Mn) in its structure
This gives it a visual similarity to other manganese-rich minerals.
Chemical Composition and Structure
Hureaulite is composed of:
- Manganese (Mn)
- Phosphate groups (PO₄ and PO₃OH)
- Water (H₂O)
It is a hydrated phosphate, meaning water molecules are part of its crystal structure, influencing:
- Stability
- Formation conditions
Formation and Geological Occurrence
Hureaulite forms in oxidized zones of manganese-rich deposits, particularly:
Secondary Environments
- Alteration of primary manganese minerals
Pegmatitic and Hydrothermal Settings
- Phosphate-rich conditions
Typical formation conditions include:
- Low to moderate temperatures
- Presence of manganese and phosphate-rich fluids
It is commonly associated with:
- Lithiophilite
- Triphylite
- Vivianite
- Other manganese phosphates
Common Locations
Hureaulite is found in several notable regions:
- France: Type locality (Limoges area)
- Portugal: Classic phosphate deposits
- United States: New Hampshire
- Brazil: Pegmatite occurrences
French and Portuguese specimens are especially well known.
Uses and Practical Significance
Hureaulite has no industrial use due to its rarity.
It is valued for:
Collector Mineral
- Attractive pink crystals
- Association with rare phosphate minerals
Similar and Related Minerals
Hureaulite can resemble:
- Vivianite: Typically blue-green rather than pink
- Ludlamite: Green iron phosphate
- Eosphorite: Also pink but different composition
Color and mineral associations help distinguish it.
Identification Notes for Collectors
- Look for pink to reddish prismatic crystals
- Note moderate softness (4–5)
- Observe vitreous luster
- Check association with manganese phosphate minerals
- Consider occurrence in oxidized deposits
Hureaulite is a hydrated manganese phosphate mineral, recognized for its pink coloration and formation in manganese-rich environments, making it an attractive and collectible mineral.