Faustite
Current inventory:  0 gems
 

  
Faustite was named to honor Dr. George Tobias Faust (1908–1985), mineralogist and geologist, U.S. Geological Survey.

Discovered in 1953;   IMA status:  Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

(Zn,Cu)Al₆(PO₄)₄(OH)₈•4.5(H₂O)

Hydrated Zinc Copper Aluminum Phosphate Hydroxide

Molecular Weight:

823.92 gm

Composition:

Aluminum

19.65 %

Al

37.13 %

Al₂O₃

Zinc

6.35 %

Zn

7.90 %

ZnO

Copper

1.54 %

Cu

1.74 %

Cu₂O

Phosphorus

15.04 %

P

34.46 %

P₂O₅

Hydrogen

2.08 %

H

18.59 %

H₂O

Oxygen

55.34 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/D.15-50

Nickel-Strunz 10th Ed. ID:

8.DD.15

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H₂O
D : With only medium-sized cations, (OH, etc.):RO₄= 2:1

Related to:

Turquoise Group. The zinc analogue of Turquoise.

Varieties:

Cuprofaustite (copper bearing Faustite)

Synonyms:

n/a

Crystal Data

Crystallography:

Triclinic - Pinacoidal

Crystal Habit:

Fine-grained massive, as veinlets, to 8 mm thick, and as nuggets and nodules.

Twinning:

None

Physical Properties

Cleavage:

Poor/Indistinct

Fracture:

Small Conchoidal to Smooth

Tenacity:

Brittle

Moh's Hardness:

5.5

Density:

2.92 (g/cm³) (corrected for admixed montmorillonite)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Apple-Green; Brown with a Greenish cast in transmitted light.

Transparency:

Opaque, Translucent on thin edges.

Luster:

Waxy to Dull

Refractive Index:

1.613  Biaxial  ( + )

Birefringence:

Medium

Dispersion:

Weak

Pleochroism:

None

Occurances

Geological Setting:

In argillized shales associated with copper mineralization (Copper King mine, Nevada, USA).

Common Associations:

Montmorillonite, Apatite, Chrysocolla, Azurite, Malachite, Cuprite, Kaolinite, Quartz, Alunite (Copper King mine, Nevada, USA).

Common Impurities:

n/a

Type Locality:

Copper King mine, Schroeder Mt, Maggie Creek District, Eureka Co., Nevada, USA

Year Discovered:

1953

View mineral photos:

Faustite Mineral Photos and Locations

More Information

Mindat.org  
Webmineral.com

Faustite is a rare zinc analog of Turquoise. It is closely related to Turquoise with the substitution of zinc in place of iron in its chemical composition. Faustite is typically apple-green with a waxy to dull luster and properties similar to Turquoise.

Faustite is found in a limited number of localities including in the USA, from the Copper King mine, about 16 km northwest of Carlin, Maggie Creek district, Eureka County, and the Rain mine, Carlin district, Elko County, Nevada; at the Bingham mine, Salt Lake County, Utah. In the Iron Monarch quarry, Iron Knob, South Australia. At the Phoenix United mines, Linkinhorne, Cornwall, England. In the Virneberg mine, near Rheinbreitbach, Rhineland-Palatinate, and at Rengersdorf, Lausitz, Saxony, Germany.
 

  
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