Phosphophyllite
Current inventory:  3 gems
 

  
Phosphophyllite is named in allusion to its composition, being a phosphate, and structure, from the Greek word phyllos for leaf, referring to its perfect cleavage.

Discovered in 1920;   IMA status: Valid (pre-IMA; Grandfathered).

Chemistry

Chemical Formula:

Zn₂Fe(PO₄)₂ • 4(H₂O)  Note: material from Bolivia lacks Manganese (Mn)

Hydrated Zinc Iron Phosphate

Molecular Weight:

448.40 gm

Composition:

Manganese

3.06 %

Mn

3.95 %

MnO

Zinc

29.17 %

Zn

36.30 %

ZnO

Iron

9.34 %

Fe

12.02 %

FeO

Phosphorus

13.82 %

P

31.66 %

P₂O₅

Hydrogen

1.80 %

H

16.07 %

H₂O

Oxygen

42.82 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/C.11-10

Nickel-Strunz 10th Ed. ID:

8.CA.40

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H₂O
A : With small and large/medium cations

Related to:

None

Varieties:

None

Synonyms:

"The holy grail of minerals"

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals tend to be thick tabular on {100}, with {110}, {011}, {102}, {111}, {311}, many other forms, to 13 cm.

Twinning:

Common as contact twins giving “fishtail” shapes and as penetration twins, may be polysynthetic.

Physical Properties

Cleavage:

Perfect on {100}, Distinct on {010} and {102}

Fracture:

Uneven

Tenacity:

Brittle

Moh's Hardness:

3.0 - 3.5

Density:

3.08 - 3.13 (g/cm³)

Luminescence:

Fluorescent; violet under SW UV

Radioactivity:

Not Radioactive

Other:

Soluble in acids.

Optical Properties

Color:

Pale bluish green, sea-green, colorless; colorless in transmitted light.

Transparency:

Transparent

Luster:

Vitreous

Refractive Index:

1.595 - 1.620  Biaxial ( - )

Birefringence:

0.0210 - 0.0330

Dispersion:

Perceptible, r > v

Pleochroism:

X = colorless, Y = pale blue green, Z = pale blue green

Occurances

Geological Setting:

Typically a secondary mineral in zoned complex granite pegmatites, an alteration product of sphalerite and Fe–Mn phosphates; in hydrothermal vein deposits.

Common Associations:

Triplite, Triphylite, Sphalerite, Apatite, Vivianite, Rockbridgeite, Strengite, Phosphosiderite, Fairfieldite (Hagendorf, Germany).

Common Impurities:

Mn

Type Locality:

Hagendorf North Pegmatite (Meixner Feldspar Pit), Hagendorf, Waidhaus, Vohenstrauß, Oberpfälzer Wald, Upper Palatinate, Bavaria, Germany

Year Discovered:

1920

View mineral photos:

Phosphophyllite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Phosphophyllite's name means phosphate leaf in allusion to both its chemistry and its perfect cleavage. It is an extremely rare mineral and is one of the rarest gems in the world. Phosphophyllite is highly prized by both mineral specimen collectors and gem collectors for its unique and beautifully delicate bluish-green color. As a testament to its rarity, Phosphophyllite has been called "the holy grail of minerals."

Phosphophyllite is a rare zinc phosphate mineral that is only found in a few locations. Gem-quality crystals only come from the Unificada Mine, Cerro Rico, Potosí City, Potosí Department, Bolivia. The first crystals were found there in the mid-1950's in the Krause vein. None have been found since that are nearly as beautiful. Crystals have also been found at the Cornelia Mine, Hagendorf, Bavaria, Germany but these are very small and pale and do not come close to the amazing color of crystals from Bolivia. Very small, pale crystals have also been found at the Foote Mine, Kings Mountain District, Cleveland County, North Carolina, USA. Both of these locations only produce very small crystals that are too small to facet. Faceted gems are extremely rare because Phosphophyllite crystals are usually kept as mineral specimens. Most crystals found at the famous Bolivian locality are kept by mineral collectors so gem grade crystals are rarely available. Usually only broken crystals and fragments are used to facet gems so gems are typically small. Phosphophyllite crystals and gems are among the hardest to obtain and the most expensive.

Distribution: From the Type Locality at Hagendorf, Bavaria, Germany. At Pribyslavice, Czech Republic. From the Norrö pegmatite, on Rånö Island, Sweden. Extraordinary crystals in the Unificada mine, Cerro Rico, and from the Siglo XX mine, Llallagua, Potosí; in the Morococala mine, near Oruro, Bolivia. In the USA, at the Palermo #1 mine, near North Groton, Grafton County, New Hampshire; at Red  Hill, Rumford, and from Newry, Oxford County, Maine. On Reaphook Hill, near Blinman, Flinders Ranges, South Australia. From Kabwe (Broken Hill), Zambia.
 

  
Phosphophyllite gems for sale: