THE MINERAL PHOSPHOPHYLLITE

Chemistry: Zn2(Fe, Mn)(PO4)2 - 4H2O , Hydrated Zinc Iron Manganese Phosphate.
Class: Phosphates
Uses: As collector's gemstone and as mineral specimens.
Specimens

Phosphophyllite, whose cumbersome name means "phosphate leaf" in allusion to both its chemistry and cleavage, is a rare zinc and manganese mineral that is found at only a few localities. It can be most appreciated when cut into gemstones that possess a good blue-green color. Gemmy phosphophyllite comes from its Bolivian locality where it formed as a primary precipitate in tin rich hydrothermal veins. In Germany and in New Hampshire, it is found as an alteration product of primary phosphates such as triphylite.

PHYSICAL CHARACTERISTICS:

Color is blue-green to colorless, gray or black (the latter probably from inclusions).
Luster is vitreous.
Transparency crystals are transparent to translucent.
Crystal System is monoclinic; 2/m.
Crystal Habits include equant to prismatic individual crystals. Twinning is common and produces a fishtail contact twin.
Cleavage is perfect in one direction and distinct in another.
Fracture is conchoidal.
Hardness is 3 - 3.5
Specific Gravity is approximately 3.1 (slightly above average for translucent minerals)
Streak is white.
Associated Minerals include triphylite, cassiterite, mica and sulfide ores.
Notable Occurrences are limited to San Luis Potosi, Bolivia; Palermo Mine, North Groton, New Hampshire, USA and Hagendorf, Germany.
Best Field Indicators are crystal habit, cleavage, locality and color.