Strengite with Phosphosiderite
Strengite with Phosphosiderite
- Sold
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- Availability
- Sold
- Size
- 5.5 x 5 x 3.5 cm - Sm Cabinet
- Formula
- Fe3+PO4·2H2O (RRUFF)
- Locality
- Bull Moose mine, Custer Co., South Dakota, United States
- Tagged
- phosphate
Strengite and Phosphosiderite are polymorphs- they have the same chemical formula, but belong to different crystal systems. Phosphosiderite is monoclinic, while Strengite is orthorhombic. At the Bull Moose mine, the two are difficult to discern. But careful observation will usually help. The Phosphosiderite are typically more prismatic, showing striation along the c-axis and the terminations will be diamond shaped. Phosphosiderite will also twin (see Jason Smith's photo on Mindat). The best crystals are a raspberry red (see Edgar Müller photo on Mindat). But color is not reliable as Strengite can also be the same color but usually not that red. The Strengite at the Bull Moose are more equant and show some octahedral faces. Saul Krotki's photo on Mindat shows a good distiction between the two. This is not the best specimen, but is a good representative of the Strengite with a little Phosphosiderite. The matrix is dull black Barbosalite with some Pyrite.
Strengite
- Formula
- Fe3+PO4·2H2O
- Crystal System
- Orthorhombic
- Crystal Habit
- Spherical, Radial, Botryoidal
- Cleavage
- Good, Poor, None
- Luster
- Vitreous (Glassy)
- Color
- colorless, pale violet, deep violet, red, carmine red
- Streak
- white
- Class
- Orthorhombic - Dipyramidal
- Fracture
- Brittle - Conchoidal
- Hardness
- 3.5
Data courtesy of Webmineral.
- Collection
- Phillips Collection
- Mineralpedia
- View Strengite
- On Dakota Matrix
- Previously Sold Strengite
- On Dakota Matrix
- Other Available Strengite
- WebMineral
- View Strengite
- Mindat
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