The Mineral STRUNZITE

Chemistry: MnFe2(PO4)2(OH)2 - 6H2O, Hydrated Manganese Iron Phosphate Hydroxide.
Class: Phosphates
Uses: Only as mineral specimens.
Specimens

Strunzite forms wonderful yellow acicular crystals that form sprays of radiating crystals. It is one of the rare phosphate minerals that comes from classic mineral localities such as Hagendorf, Germany and the Palermo Mine in New Hampshire. It is closely related to the mineral laueite. A casual look at laueite's formula, MnFe2(PO4)2(OH)2 - 8H2O, might lead you to think its the same as strunzite's. But a closer inspection reveals the only difference being two more water molecules in laueite's formula. Those two water molecules make a difference in the structure and a difference in the crystal habit of the two minerals. Laueite forms tabular crystals in contrast to strunzite's acicular or hair-like crystals.

PHYSICAL CHARACTERISTICS:

Color is bright straw yellow to brown-yellow or brown.
Luster is vitreous to silky.
Transparency: Specimens are translucent to transparent.
Crystal System is triclinic (pseudo-monoclinic).
Crystal Habits include acicular to fibrous crystals in radiating sprays and in fibrous crusts.
Cleavage is absent.
Fracture is uneven.
Hardness is 3
Specific Gravity is approximately 2.5 - 2.6 (average).
Streak is white.
Associated Minerals include limonite, triphylite, rockbridgeite, beraunite, laueite and other phosphate minerals.
Notable Occurrences includes Hagendorf, Germany; Palermo Mine, New Hampshire and the Black Hills region of South Dakota USA.
Best Field Indicators are color, locality, crystal habit, associations and lack of cleavage.