Brazilianite
Current inventory:  2 gems
 

  
Brazilianite is named after its discovery in Brazil.

Discovered in 1945;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

NaAl₃(PO₄)₂(OH)₄

Sodium Aluminum Phosphate Hydroxide

Molecular Weight:

361.91 gm

Composition:

Sodium

6.35 %

Na

8.56 %

Na₂O

Aluminum

22.37 %

Al

42.26 %

Al₂O₃

Phosphorus

17.12 %

P

39.22 %

P₂O₅

Hydrogen

1.11 %

H

9.96 %

H₂O

Oxygen

53.05 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/B.12-10

Nickel-Strunz 10th Ed. ID:

8.BK.05

8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H₂O
K : With medium-sized and large cations, (OH, etc.):RO₄ = 2:1, 2.5:1

Related to:

n/a

Varieties:

None

Synonyms:

Brazilianite (of Pough and Henderson)

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Typically Euhedral Crystals - occurs as well-formed crystals showing good external form. May also be spherical, rounded aggregates or radial fibrous or globular.

Twinning:

None

Physical Properties

Cleavage:

Good on {010}

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

5.5

Density:

2.98 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive Slowly decomposed by HF and by hot H2SO4.

Other:

Slowly decomposed by HF and by hot H2SO4.

Optical Properties

Color:

Colorless, Greenish yellow, Yellow green, Light yellow

Transparency:

Transparent

Luster:

Vitreous (glassy)

Refractive Index:

1.602 - 1.623  Biaxial ( + )

Birefringence:

0.0190 - 0.0210

Dispersion:

Perceptible; 0.014; r < v

Pleochroism:

Weak; merely a change in shade of color

Occurances

Geological Setting:

A hydrothermal mineral in phosphate-rich zones of granite pegmatites; also in metamorphosed sedimentary deposits.

Common Associations:

Muscovite, Albite, Apatite, Tourmaline (Córrego Frio mine, Brazil); Whitlockite, Apatite, Quartz (Palermo #1 mine, New Hampshire, USA); Amblygonite, Lazulite-Scorzalite, Augelite, Bertossaite, Apatite (Buranga pegmatite, Rwanda).

Common Impurities:

None

Type Locality:

Conselheiro Pena, Doce valley, Minas Gerais, Southeast Region, Brazil

Year Discovered:

1945

View mineral photos:

Brazilianite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Brazilianite is a rare and beautiful gem with a wonderful lemon yellow color. It was discovered in Minas Gerais, Brazil in 1945. Large crystals are rare and usually kept for mineral collections making gems even harder to come by. Gems are often moderately included and clean gems are very rare. Brazilianite is not very hard by gemstone standards, but it is one of the hardest phosphate minerals. Gems are typically included and large, clean gems are very rare.

Current sources of Brazilianite crystals are Linopolis and Minas Gerais, Brazil; Sullivan County, New Hampshire, USA; Oxford County, Maine, USA; Yavapai County, Arizona, USA; and Rapid Creek area, Yukon Territory, Canada.
 

  
Brazilianite gems for sale: