Allanpringite

Allanpringite is a phosphate mineral named after Australian mineralogist Allan Pring, South Australian Museum. It was named to honor Australian mineralogist Dr. Allan Pring. Allanpringite is a ferric iron phosphate that is found only at the type locality at Grube Mark near Essershausen in Hesse, Germany. Allanpringite is a Fe3+ analogue Al-phosphate mineral wavellite, but it has a different crystal symmetry – monoclinic instead of orthorhombic in wavellite.

It forms needle-like crystals, which are always twinned and form parallel bundles up to about 2 mm long. t is closely related to wavellite and is associated with beraunite, cacoxenite, strengite, and cryptomelane. It appears as pale yellow-brown acicular crystals that are intergrown into bundles. They are often found in association with other iron phosphates in abandoned iron mines. It is not Radioactive.

General Information

  • Category: Phosphate mineral
  • Formula: Fe33+(PO4)2(OH)35H2O
  • Crystal system: Monoclinic
  • Crystal class: Prismatic (2/m)
  • Density: 2.54(2) g/cm3 (Measured) and 2.583 g/cm3 (Calculated)

Identification

The mineral occurs as pale brown-yellow, [010] acicular, invariably twinned (by nonmerohedry) crystals which are always intergrown to form bundles of subparallel individuals. The maximum length of crystals is ca. 1.5 mm (usually much smaller); bundles can reach up to about 2 mm. The mineral is associated with beraunite (reddish “oxiberaunite” variety), cacoxenite, strengite, and cryptomelane.

  • Formula mass: 498.07 g/mol
  • Color: Pale brownish yellow
  • Crystal habit: Acicular
  • Cleavage: {hk0} perfect, {010} good
  • Fracture: Irregular/uneven
  • Tenacity: Brittle
  • Mohs scale hardness: 3
  • Luster: Vitreous
  • Streak: Pale yellowish white
  • Diaphaneity: Translucent to transparent
  • Specific gravity: 2.54 (means.), 2.583 (calc.)

Allanpringite is translucent to transparent, its streak is white with a pale yellowish tint, and it has a vitreous luster. It shows a perfect cleavage parallel to the morphological elongation and one good cleavage parallel to {010}.

 

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