Phosphophyllite

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Phosphophyllite
Phosphophyllite-359315.jpg
General
Category Phosphate minerals
Formula
(repeating unit)
hydrated zinc phosphate Zn2Fe(PO4)2•4H2O
Strunz classification 8.CA.40
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group P21/c
Identification
Formula mass 448.40 g/mol
Colour blue-green to colourless
Crystal habit prismatic
Twinning common
Cleavage [100] Perfect, [010] Distinct, [102] Distinct
Fracture conchoidal
Mohs scale hardness 3.5
Lustre vitreous
Streak white
Diaphaneity transparent
Specific gravity 3.1
Refractive index 1.59-1.62
Birefringence 0.021
Common impurities manganese
References [1]

Phosphophyllite is a rare mineral composed of hydrated zinc phosphate. Its name derives from its chemical composition (phosphate) and the Greek word for "leaf", phyllon, a reference to its cleavage.[2] It is highly prized by collectors for its rarity and for its delicate bluish green colour. Phosphophyllite is rarely cut because it is fragile and brittle, and large crystals are too valuable to be broken up.[3]

The finest phosphophyllite crystals come from Potosí, Bolivia, but it is no longer mined there. Other sources include New Hampshire, US and Hagendorf, Bavaria, Germany. It is often found in association with the minerals chalcopyrite and triphylite.[4]

Twinned Phosphophyllite, Unificada Mine, Cerro de Potosí, Potosí Department, Bolivia. 2.1 x 1.4 x 1 cm.

References[edit]

  1. ^ Mineralienatlas
  2. ^ "Phosphophyllite". Retrieved 2006-12-16. 
  3. ^ Hall, Cally (1994). Gemstones. Great Britain: Dorling Kindersley. p. 127. ISBN 0-7513-1026-3. 
  4. ^ "The mineral phosphophyllite". Amethyst Galleries, Inc. Retrieved 2006-12-16. 

External links[edit]