Burangaite
Current inventory: 0 gems
 

  
Burangaite was named for the type locality at the Buranga pegmatite, Gatumba District, Western Province, Rwanda.

Discovered in 1976; IMA status: Valid (IMA Approved 1976)

Chemistry

Chemical Formula:

(NaCa)(Fe²⁺Mg)Al₅(PO₄)₄(OHO)₆ • 2(H₂O)

Hydrated Sodium Calcium Iron Manganese Phosphate Hydroxide

Molecular Weight:

738.18 gm

Composition:

Sodium

2.18 %

Na

2.94 %

Na₂O

Calcium

1.63 %

Ca

2.28 %

CaO

Magnesium

1.32 %

Mg

2.18 %

MgO

Aluminum

18.28 %

Al

34.53 %

Al₂O₃

Iron

6.05 %

Fe

6.81 %

FeO / 1.08 % Fe₂O₃

Phosphorus

16.78 %

P

38.46 %

P₂O₅

Hydrogen

1.31 %

H

11.71 %

H₂O

Oxygen

52.45 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/D.11-120

Nickel-Strunz 10th Ed. ID:

8.DK.15

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H₂O
K : With large and medium-sized cations, (OH, etc.):RO₄ > 1:1 and < 2:1

Related to:

Dufrénite Group. Burangaite-Matioliite Series. Fe2+ analogue of Matioliite.

Members of Group:

Dufrénite Group: Burangaite, Dufrénite, Gayite, Matioliite, Natrodufrénite 

Varieties:

None

Synonyms:

IMA1976-013

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals are prismatic, bladed, elongated along [010], bounded by {h0l} forms, and complexly terminated by {311} and {223}; may be fibrous. 

Twinning:

None

Physical Properties

Cleavage:

Perfect on {100}

Fracture:

n/a

Tenacity:

Brittle

Moh's Hardness:

5.0

Density:

3.05 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Bluish to blue-green; commonly shows a zoned hourglass structure, centrally blue with colorless margins.

Transparency:

Semi-transparent

Luster:

n/a

Refractive Index:

1.611 - 1.643  Biaxial ( + )

Birefringence:

0.032

Dispersion:

Relatively strong; r > v

Pleochroism:

Strong; X = light blue; Y = dark blue; Z = colorless

Occurances

Geological Setting:

In corroded aggregates of other phosphates in a zoned granite pegmatite (Buranga pegmatite, Rwanda).

Common Associations:

Scorzalite, Bjarebyite, Bertossaite, Trolleite, Samuelsonite, Gatumbaite, Wardite, Brazilianite, Apatite, Quartz (Buranga pegmatite, Rwanda); Berlinite, Lazulite, Scorzalite, Augelite, Gatumbaite, Trölleite, Rutile (Hålsjöberg, Sweden).

Common Impurities:

None

Type Locality:

Buranga pegmatite, Gatumba District, Western Province, Rwanda

Year Discovered:

1976

View mineral photos:

Burangaite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Burangaite is a very rare phosphate mineral that is a member of the Dufrénite Group of minerals. It was discovered in 1976 at the Buranga pegmatite, Gatumba District, Western Province, Rwanda and named for this locality. Burangaite is typically blue to blue-green in needle-like crystals and often found associated with Apatite, Bertossaite, Brazilianite, Quartz, Scorzalite, Trolleite and Wardite. The gem pictured above shows royal blue Burangaite with faintly pinkish to white Bertossaite.

Burangaite was named for the type locality at the Buranga pegmatite, Gatumba District, Western Province, Rwanda.

Burangaite distribution: in the Buranga pegmatite, near Gatumba, Western Province, Rwanda. At Hålsjöberg, Värmland, Sweden. From the Gold Quarry mine, near Carlin, Maggie Creek district, Eureka County, Nevada, USA.
 

  
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