Names
Naldrettite
Intro
Naldrettite is a rare palladium antimonide mineral (Pd2Sb) discovered in the Sudbury mining district, forming under late-magmatic hydrothermal conditions within nickel-copper sulfide deposits.
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Basic Information Show Hide
Mineral ID
naldrettite
Common Synonyms / Aliases
Antimonide of palladium, Pd2Sb
Chemistry Show Hide
Chemical Formula
Pd2Sb
Elements
Pd, Sb
Minor Elements / Impurities
Fe, Ni, As
Empirical Formula
Pd2.00Sb1.00
Molecular Weight (g/mol)
334.60
Solubility
Insoluble in water and cold acids
Reaction to Acid
Slowly attacked by hot concentrated aqua regia
Classification Show Hide
Mineral Type
Mineral Species
IMA Status
Approved
IMA Symbol
Nld
Strunz Classification
02.AC.25c
Dana Classification
02.04.18.01
Mineral Group
Sulfides and Sulfosalts (Intermetallic compounds)
Crystal Structure Show Hide
Crystal System
Orthorhombic
Crystal Habit
Microscopic anhedral to subhedral grains, intergrown with sulfides
Crystal Class
Orthorhombic Dipyramidal (2/m 2/m 2/m)
Space Group
C2221
Cell Parameter A (Angstrom)
3.390
Cell Parameter B (Angstrom)
17.555
Cell Parameter C (Angstrom)
6.957
Cell Angle Alpha (Degrees)
90
Cell Angle Beta (Degrees)
90
Cell Angle Gamma (Degrees)
90
Unit Cell Z
8
Crystal Twinning
None reported
Common Crystal Faces
Indetermined due to microscopic grain size
Physical Properties Show Hide
Primary Color
White
Common Colors
Bright Cream White, Light Cream
Streak
Metallic Gray
Luster
Metallic
Transparency / Diaphaneity
Opaque
Hardness (Mohs)
4 - 5
Cleavage
None
Cleavage Direction
N/A
Cleavage Angle / Parting Quality
None
Fracture
Irregular / Uneven
Tenacity
Brittle
Specific Gravity
10.69 - 10.73
Magnetism
Non-magnetic
Melting Point
>800 °C
Thermal Stability
Stable under low-to-moderate temperature magmatic-hydrothermal settings
Optical Properties Show Hide
Dispersion
Not reported
Optical Character
Isotropic
Pleochroism
Weak to moderate in reflected light (cream-white to slightly darker cream)
Pleochroism Details
Observed under reflected light microscopy
Optical Phenomena
High reflectance with distinct bireflectance
Fluorescence
Non-fluorescent
Luminescence / Phosphorescence / Thermoluminescence
Non-fluorescent
Absorption Spectrum
N/A
Occurrence and Formation Show Hide
Formation Process
Formed during late-stage magmatic crystallization and low-temperature hydrothermal fluid interaction rich in antimony and palladium.
Geological Environment
Magmatic Ni-Cu-PGE sulfide deposits
Associated Minerals
Chalcopyrite, Galena, Pyrrhotite, Pentlanite, Gold, Suessite
Type Locality
Fraser Mine, Levack Township, Sudbury District, Ontario, Canada
Major Producing Countries / Localities
CanadaRussia
Economic Deposit Type
Magmatic hydrothermal PGE deposit
History and Naming Show Hide
Discovery Year
2004
Name Origin
Named after Anthony J. Naldrett, a prominent Canadian economic geologist and expert on magmatic sulfide deposits.
Type Specimen Repository
Systematic Collection of the Geological Survey of Canada, Ottawa
Safety and Related Information Show Hide
Wearability
Poor
Health Hazards
Contains heavy metals (palladium) and antimony; toxic if inhaled as dust or ingested.
Handling Precautions
Avoid inhalation of dust during handling or polishing; wash hands after contact.
Varieties
None
Polytypes
None
Related Minerals
Michenerite, Froodite, Sudburyite, Mertieite
Commercial and Gemology Show Hide
Common Treatments
None reported
Enhancements
None reported
Common Cuts
Polished sections or micro-mounts only.
Rarity / Market Grade
Extremely rare
