Editorial Feature

Arsenopalladinite - Occurrence, Properties, and Distribution

May 20 2014

Arsenopalladinite is a triclinic-pedial silver-white mineral, containing palladium, arsenic, and antimony. The mineral was first discovered in Itabira, Minas Gerias in Brazil in 1974. It was named after the palladium and arsenic in its composition.

Properties of Arsenopalladinite

The following are the key properties of Arsenopalladinite:

Cell Data
- Space Group: P1
- a = 7.43
- b = 13.95
- c = 7.35
- α = 92°53'
- β = 119°30'
- γ = 87°51'
- Z = 6

Crystal Data
- Triclinic
- Point Group: 1
- As rounded grains, to 1.8mm
- X-ray Powder Pattern: 2.13 (100), 2.34 (60), 1.41 (40), 1.24 (30), 1.21 (30), 2.28 (20), 2.19 (20)

Chemical Composition

Elements Content

Pd 77.56

As 17.08

Sb 5.15

Cu 0.02

Total 99.81

Elements	Content
Pd	77.56
As	17.08
Sb	5.15
Cu	0.02
Total	99.81

Optical Properties
- R1–R2: (400) 43.9–44.5, (420) 44.7–45.8, (440) 45.7–46.5, (460) 46.8–47.8, (480) 48.1–49.4, (500) 49.4–50.8, (520) 50.8–52.4, (540) 52.1–53.9, (560) 53.2–55.1, (580) 54.4–56.4, (600) 55.4 57.3, (620) 56.4–58.1, (640) 57.0–58.8, (660) 57.7–59.2, (680) 58.2–59.8, (700) 58.8–60.0

Estimated Properties

Electron density	Bulk density (electron density) = 9.55 g/cm³ note: Specific gravity of Arsenopalladinite = 11 g/cm³
Photoelectric	PE_{Arsenopalladinite} = 218.6 barns/electron U = PE_{Arsenopalladinite} x ρ Electron density = 2087.65 barns/cm³
Fermion index	Fermion index = 0.17 Boson index = 0.83
Radioactivity	Arsenopalladinite is not radioactive

How to Identify Arsenopalladinite

Arsenopalladinite is a silver-white mineral, having metallic luster and opaque appearance. It can be formed as anhedral grains or irregular lumps, produced by stream transport of malleable metals.

The density of arsenopalladinite is 10.4 g/cm³, and its hardness is 4.

Global Distribution

Arsenopalladinite is distributed in the following places:

Minas Gerais, in the Itabira district, Brazil
Caue iron mine, Brazil
Stillwater complex, Montana, USA
Merensky Reef, Bushveldt complex, Transvaal, South Africa
Siikakama and Konttijarvi intrusions, northern Finland

Occurrence of Arsenopalladinite and Useful Mineral Association

Arsenopalladinite occurs in gold concentrates.

It is closely associated with hollingworthite, sperrylite, vysotaskite, braggite, stillwaterite, palladesite, palladium, gpold, quartz, isomertieite, atheneite, and hematite.