Phosphophyllite

Phosphophyllite
General
Chemical formula	hydrated zinc phosphate Zn2(Fe,Mn)(PO4)2•4H2O
Identification
Molecular Weight	448.40 g mol-1
Color	blue-green to colourless
Crystal habit	prismatic
Crystal system	monoclinic
Twinning	common
Cleavage	[100] Perfect, [010] Distinct, [102] Distinct
Fracture	conchoidal
Mohs Scale hardness	3.5
Luster	vitreous
Refractive index	1.59-1.62
Birefringence	0.021
Streak	white
Specific gravity	3.1
Diaphaneity	transparent

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.[1] 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.[2]

The finest phosphophyllite crystals come from Potosí, Bolivia, but it is no longer mined there. Other sources include New Hampshire, USA and Hagendorf, Bavaria, Germany. It is often found in association with the minerals chalcopyrite and triphylite.[3]

References

1. ^ "Phosphophyllite". http://webmineral.com/data/Phosphophyllite.shtml. Retrieved on 2006-12-16.
2. ^ Hall, Cally (1994). Gemstones. Great Britain: Dorling Kindersley. p. 127. ISBN 0-7513-1026-3.
3. ^ "The mineral phosphophyllite". Amethyst Galleries, Inc. http://mineral.galleries.com/minerals/phosphat/phosphop/phosphop.htm. Retrieved on 2006-12-16.

List of minerals