The Mineral BERAUNITE

Chemistry: Fe₆(PO₄)₄(OH)₅ - 4H₂O, Hydrated Iron Phosphate Hydroxide.
Class: Phosphates
Uses: Only as mineral specimens.
Specimens

Beraunite is a scarce, but popular phosphate mineral for collectors. It can have a nice color and luster and its rarity make it an ideal collection specimen. It is one of those minerals that contain two valences of iron and its formula could be written to reflect this fact as in :Fe{+2}Fe{+3}₅(PO₄)₄(OH)₅ - 4H₂O. This chemistry reflects the fact that the mineral formed in not quite completely oxidized conditions, a situation that interests geochemists. The larger Fe{+2} ion occupies a separate and distinct position in the structure of beraunite from the five other Fe{+3} ions.

PHYSICAL CHARACTERISTICS:

Color is yellow, brown, red, green or yellow.
Luster is vitreous.
Transparency: Specimens are translucent to transparent.
Crystal System is monoclinic.
Crystal Habits include acicular, tabular, encrusting or radiating fibrous crystals.
Cleavage is good.
Fracture is uneven.
Hardness is 3 - 4
Specific Gravity is approximately 2.9 (average).
Streak is yellow.
Associated Minerals include strengite, cacoxenite, strunzite, rockbridgeite and limonite.
Notable Occurrences include Cornwall, England; Ireland; Germany; Palermo Mine, New Hampshire and Pennington County, South Dakota, USA.
Best Field Indicators are crystal habit, color, associations, cleavage and streak.

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BERAUNITE specimens:
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BERAUNITE specimen bea-1
$ 49.00

Dims: 1.9 x 1.6 x 1.3" (4.8 x 4.1 x 3.2 cm)

Wt: 1.7 oz. (48 g)

Shady Community, Polk County, Arkansas, U.S.A.

Several round Beraunite nodules rest on the iron-rich base rock of this hand specimen. These nodules do not exceed 0.1" (3 mm) in diameter but are in excellent condition, showing almost no damage. They show no identifiable crystal form other than their nodular habit, and are a pale green color and have a dull, matte luster.

bea-1 ($ 49.00)

Shady Community, Polk County, Arkansas, U.S.A.

BERAUNITE specimen bea-2
$ 30.00

Dims: 2.1 x 1.7 x 0.6" (5.2 x 4.2 x 1.6 cm)

Wt: 1.2 oz. (35 g)

Chino Mine, Santa Rita, Grant County, New Mexico, U.S.A.

Many tiny, damaged Bereaunite nodules rest on the brown base of this hand specimen. These nodules do not exceed 1 or 2 mm in diameter, and all are broken to reveal the compact, radial nature of the crystals. Their color is nearly black, showing a hint of blue, and all have a dull pearly to waxy luster. These nodules rest on a compact, fibrous or bladed layer of rusty-brown crystals that I cannot identify- given possible associations, I would guess cacoxenite or, less likely, strunzite.

bea-2 ($ 30.00)

Chino Mine, Santa Rita, Grant County, New Mexico, U.S.A.