Azurite - Occurrence, Properties, and Distribution

Azurite is a soft, deep blue copper mineral first observed in Tsumeb near Otavi, Namibia. The mineral was named after the Persian lazhward, for its characteristic blue color.

Properties of Azurite

The following are the key properties of Azurite:

• Cell Data
  • Space Group: P2₁/c
  • a = 5.0109(5)
  • b = 5.8485(6)
  • c = 10.345(2)
  • β = 92.43(3)°
  • Z = 2
• Crystal Data
  • Monoclinic
  • Point Group: 2/m
  • Crystals are typically complex, with over 100 forms recorded, to 30 cm. Tabular on {001}, less commonly so on {102} or {102}; short to long prismatic along [001], with prominent {110} and {100}, or along [010], with wedgelike terminations. As rhomboidal, lenticular, or spherical subparallel aggregates, which may form rosettes; also as internally radial stalactitic or columnar aggregates; botryoidal, drusy, earthy, massive
  • Twinning: Rare; twin planes {101}, {102}, {001}
  • X-ray Powder Pattern: 3.516 (100), 2.224 (70), 5.15 (55), 3.674 (50), 2.510 (35), 2.287 (35), 5.08 (30)
• Chemical Composition

  Elements	Content 1	Content 2
  CuO	66.34	67.27
  SO3	22.32	22.57
  H2O	10.52	10.16
  Total	100.06	100

• Optical Properties
  • Optical Class: Biaxial (+)
  • Pleochroism: In shades of blue
  • Orientation: X = b; Z ^ c =–12°36'
  • Dispersion: r > v, strong
  • Absorption: Z > Y > X
  • α = 1.730
  • β = 1.754–1.758
  • γ = 1.835–1.838
  • 2V(meas.) = 67°
• Estimated Properties

  Electron density	Bulk density (electron density)=3.67 g/cm3 note: Specific gravity of Azurite =3.83 g/cm3
  Photoelectric	PEAzurite = 24.43 barns/electron U= PEAzurite x ρ Electron density= 89.58 barns/cm3
  Fermion index	Fermion index = 0.0009 Boson index = 0.99
  Radioactivity	Azurite is not radioactive

How to Identify Azurite

Azurite can be observed in azure blue, blue, light blue or dark blue color. It has transparent to subtranslucent appearance, non-fluorescent luminescence, vitreous luster, light blue streak and perfect cleavage.

It exhibits very brittle fracture producing small, conchoidal fragments. It can be formed as prismatic, stalactitic or tabular structures. The average density of the mineral is 3.83 g/cm³, and its hardness ranges from 3.5 to 4.

Global Distribution

Azurite is distributed in the following places:

• Chessy, near Lyon, Rhˆone, France
• Alghero and elsewhere on Sardinia, Italy
• Zmeinogorsk (Schlangenberg) and Zolotuskinskii mines, Altai Mountains, Russia
• Touissit mine, near Oujda, Morocco
• Chingola mine, Nchanga, Zambia
• Tsumeb, Namibia
• Morenci, Greenlee Co., Mammoth-St. Anthony mine, Pinal Co. USA
• Kelly and Graphic mines, Magdalena, Socorro Co., New Mexico
• Apex mine, St. George, Washington Co., and at the Big Indian mine, near La Sal, San Juan Co
• El Cobre mine, Concepcion del Oro, and at the San Carlos mine, Mazapil, Zacetecas, Mexico
• New South Wales, at Broken Hill, Australia
• Girilambone mine, north of Nyngan
• Yang Chweng mine, Shilu, Guangdong Province, China

Occurrence of Azurite and Useful Mineral Association

Azurite occurs in the oxidized zones of copper deposits associated with carbonate rocks. It is closely associated with dolomite, calcite, smithsonite, cerussite, cuprite, antlerite, brochantite, chrysocolla and malachite.

References

• Azurite Mineral Data – Webmineral
• Azurite.pdf- Rruff Project Website - University of Arizona