Phosphofyllite is a mineral , an aqueous zinc phosphate . Forms crystals of thick-tabular habitus and other forms, twinning of penetration and fishtail type is characteristic. The color varies from blue-green to light green, sometimes transparent crystals are found. [one]
| Phosphofillite | |
|---|---|
 Phosphophyllite crystals in the parent rock | |
| Formula | Zn 2 Fe (PO 4 ) 2 • 4H 2 O |
| Molecular mass | 448.40 |
| Impurity | Mn |
| Year of discovery | 1920 |
| IMA status | valid |
| Physical properties | |
| Colour | blue-green, light green, colorless |
| Color features | white |
| Shine | glass |
| Transparency | transparent |
| Hardness | 3–3,5 |
| Fragility | fragile |
| Cleavage | perfect over {100}, clear over {010} and {102} |
| Kink | uneven |
| Density | 3.08—3.13 g / cm³ |
| Radioactivity | 0 GRapi |
| Crystallographic properties | |
| Dot group | 2 / m - monoclinic-prismatic |
| Space group | P2 1 / c |
| Syngony | monoclinic |
| Cell parameters | a = 10.387 (9) Å b = 5.09 (1) Å c = 10.563 (9) Å β = 121.07 (7) ° |
| Axle ratio | a: b: c = 2.041: 1: 2.075 |
| The number of formula units (Z) | 2 |
| Unit cell volume | 478.35 ų |
| Twinning | Common are the fishtail twins of {100}, sometimes polysynthetic. Rarely {102} |
| Optical properties | |
| Optical type | biaxial (-) |
| Refractive index | n α = 1.595-1.599 n β = 1.614-1.617 n γ = 1.616-1.620 |
| 2V angle | measured: 44 °, calculated: 34 ° |
| Birefringence | 0.021 |
| Optical relief | moderate |
| Optical axis dispersion | r> v tangible |
| Pleochroism | not pleochroic |
| Luminescence | purple under shortwave UV |
Content
History
Phosphofillite was first found in the Hagendorf district (Waidhaus community, Bavaria ), and is described by Heinrich Laubmann and Herman Steinmetz in the 1920s. The mineral received its name from its chemical composition (phosphate) and the Greek word φύλλον, meaning “leaf”, emphasizing the perfect cleavage of the mineral. [2]
Properties
It is dissolved in acids . Sensitive to heat. [3]
Deposits
Scattering of phosphophyllite crystals on dark red sphalerite and light brown siderite |
Phosphofillite is formed in pegmatite veins and is accompanied by minerals such as sphalerite , vivianite , triplit , phosphosiderite , triphilin , fluorapatite , strand , firefieldite . [four]
Famous deposits of phosphophyllite are the Morococala mine in the province of Dalence and the mine of Unifikad in Cerro Rico de Potosí, Bolivia . Other fields include the Reaphuk Hill on the Flinders Ridge in Australia , eastern Kemptville in the Canadian province of Nova Scotia , the Maharahara mine on the island of North , New Zealand , the field near the city of Nynashamn in Sweden , and numerous deposits in the United States . [four]
Use
Due to its low hardness, phosphohllite is rarely cut and is not used in the manufacture of jewelry. However, the mineral is highly valued by collectors because of its rarity. [five]
Notes
- ↑ Phosphophyllite gemstone information .
- ↑ Laubmann, 1920 .
- ↑ Phosphophyllite .
- ↑ 1 2 Phosphophyllite mineral information and data .
- ↑ Hall, 1994 , p. 127.
Literature
- H. Laubmann, H. Steinmetz. Phosphatführende Pegmatite des Oberpfälzer und Bayerischen Waldes // Zeitschrift für Krystallographie und Mineralogie. - 1920. - T. 55 . - p . 523-586 .
- Hall, Cally. Gemstones. - Great Britain: Dorling Kindersley, 1994. - ISBN 0-7513-1026-3 .