Aerugite – Occurrence, Properties, and Distribution

Aerugite was named by Gilbert-Joseph Adam in 1869, from the Greek word aerugo, which means copper rust, in allusion to its appearance.

Properties of Aerugite

The following are the key properties of Aerugite:

• Cell Data
  • Space group: R3m (synthetic)
  • a = 5.9511(5)
  • c = 27.5676(20)
  • Z = 1

• Crystal Data
  • Hexagonal
  • Point group: 3 2/m
  • Fine-grained crystalline
  • Massive
  • As crusts, to 2mm thick
  • X-ray powder pattern: 2.060 (vvs), 3.76 (vs), 2.329 (s), 5.05 (s), 2.862 (s), 2.492 (s), 1.485 (s)

• Chemical Composition

  Elements	Content 1	Content 2	Content 3	Content 4
  NiO	62.07	60.9	61.3	64.81
  As2O5	36.57	36.3	37.6	35.19
  CoO	0.54	1.2	0.7	-
  CuO	0.34	0.3	0.7	-
  Bi2O3	0.24		-
  FeO	-	1.3	0.6	-
  P2O5	0.14	-	-	-
  Fe2O3	trace	-	-	-
  Total	99.90	[100.0]	100.9	100.00

• Optical Properties
  • Semi-transparent
  • ω = n.d
  • ε = n.d

• Estimated Properties

  Electron density	Bulk density (electron density) = 5.46 g/cm3 note: Specific gravity of Aerugite = 5.76 g/cm3
  Photoelectric	PEAerugite = 37.82 barns/electron U = PEAerugite x ρ electron density = 206.47 barns/cm3
  Fermion index	Fermion index = 0.0062 Boson index = 0.9937
  Radioactivity	Aerugite is not radioactive

How to Identify Aerugite

Aerugite can be identified in the field by its color variations, such as deep blue-green, and green. It is opaque and non-magnetic, and its encrustations form crust-like aggregates on matrix. This mineral has a greenish-white streak.

The density of aerugite is 5.85 to 5.95 g/cm³, with a hardness of 4 – approximate to fluorite.

Global Distribution

Aerugite is distributed in the following places:

• Germany - From Johanngeorgenstadt, Saxony
• England - South Terras mine, St. Stephen-in-Brannel, Cornwall

Occurrence of Aerugite and Useful Mineral Association

Aerugite occurs in a rare secondary mineral in hydrothermal Ni–As–U ore deposits.

It is often associated with minerals such as bismuth, bunsenite, xanthiosite, and xanthiosite.

References

• Aerugite -RruffProject Website-University of Arizona
• Aerugite -Webmineral
• Aerugite -Mindat