HAUCKITE

Fe³⁺₃(Mg,Mn)₂₄Zn₁₈(SO₄)₄(CO₃)₂(OH)₈₁
Hexagonal, 6/mmm Laue symmetry, a = 9.17, c = 20.21 Å, Z = 1

	Figure 24-10. Semi-rosette of platy, hexagonal hauckite crystals from Sterling Hill. Field of view is 1 mm in maximum dimension.

Hauckite was described by Dunn et al. (1980b) from Sterling Hill and was later found on Franklin material. The crystal structure is unknown.

Description

Hauckite occurs as irregular clusters and rosettes of hexagonal platy crystals (Figures 24-10 and 24-11); forms present are {0001} and {010}; and all crystals are severely flattened.

Hauckite is light orange or light yellow, with vitreous luster, perfect cleavage on {0001}, and a density of 3.02 g/cm³ (meas.), 3.10 g/cm³ (calc.). Optically, it is uniaxial, positive, with w = 1.630 and  e = 1.638; pleochroic with O = golden brown, E = pale yellow; and absorption O > E.

Composition

Hauckite is a ferric-iron magnesium manganese zinc sulfate carbonate hydroxide mineral. The original analysis yielded Al₂O₃ 0.5, Fe₂O₃ 6.0, MnO 17.1, MgO 13.2, ZnO 36.0, SO₃ 7.4, CO₂ 2.1, H₂O 17.7, total = 100.0 wt. %. Carbon and water were not individually determined, and the formula above is tentative.

Occurrence and paragenesis

Hauckite was found associated with calcite, serpentine, and mooreite in the 935 stope, between the 800 and 900 levels at Sterling Hill.

	Figure 24-11. Platy aggregate of hexagonal hauckite crystals from Sterling Hill. Field of view is 1 mm in maximum dimension.

Additional specimens of hauckite were subsequently found in the same stope near the 700 level, associated with sussexite, pyrochroite, and zincite; hauckite is the last mineral to form. Hauckite was later found in specimens from the 1100 stope on the 900 level associated with pyrochroite and lawsonbauerite, and from the 2350 level in the north orebody associated with chlorophoenicite, calcite and serpentine. It may have been moderately common in small amounts, but overlooked.

Hauckite is also known as a minor component of an intimate mixture of hemimorphite and hydrotalcite, associated with zincite, in a vein assemblage from Franklin. This occurrence was verified by X-ray diffraction only.  

Name

Hauckite was named in honor of Richard Hauck, a collector and dealer of Franklin minerals and a tireless promoter of the local mineral culture. Mr. Hauck, his wife, Elna Hauck, and his brother, Robert Hauck, deserve much recognition for their founding and nurturing of the Sterling Hill Mining Museum in Ogdensburg.

Copyright © 1995 by Pete J. Dunn			Website by Herb Yeates
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This page created: January 11, 2001