Poudretteite
Current inventory:  0 gems
 

  
Poudretteite was named to honor the Poudrette family, operators of the Poudrette quarry, Mont Sainte-Hilaire, Quebec, Canada where the material was discovered.

Discovered in 1987; IMA status: Valid (IMA approved 1987)

Chemistry

Chemical Formula:

KNa₂B₃SI₁₂O₃₀

Potassium Sodium Boron Silicate

Molecular Weight:

912.90 gm

Composition:

Potassium

4.28 %

K

5.16 %

K₂O

Sodium

5.04 %

Na

6.79 %

Na₂O

Silicon

36.92 %

Si

78.98 %

SiO₂

Boron

1.18 %

B

3.81 %

B₂O₃

Oxygen

52.58 %

O

100.00 %

94.74 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/E.22-10

Nickel-Strunz 10th Ed. ID:

9.CM.05

9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si₆O₁₈]₁₂- 6-membered double rings (sechser-Doppelringe)

Related to:

Osumilite (Milarite) Group.

Members of Group:

Osumilite (Milarite) Group: Almarudite, Armenite, Berezanskite, Brannockite, Darapiosite, Dusmatovite, Friedrichbeckeite, Klöchite, Merrihueite, Milarite, Osumilite, Osumilite-(Mg), Poudretteite, Roedderite, Shibkovite, Sogdianite, Sugilite, Trattnerite, Yagiite

Varieties:

None

Synonyms:

IMA1986-028

Crystal Data

Crystallography:

Hexagonal - Dihexagonal Dipyramidal

Crystal Habit:

As roughly equant, barrel-shaped prismatic crystals, deeply etched, to 5 mm.

Twinning:

None

Physical Properties

Cleavage:

None observed

Fracture:

Splintery to Conchoidal

Tenacity:

Brittle

Moh's Hardness:

5.0 - 6.0

Density:

2.51 (g/cm³)

Luminescence:

None

Radioactivity:

Barely Detectable, GRapi = 61.48 (Gamma Ray American Petroleum Institute Units)

Optical Properties

Color:

Colorless to pale pink

Transparency:

Transparent

Luster:

Vitreous

Refractive Index:

1.516 - 1.532  Uniaxial ( + )

Birefringence:

0.0160 - 0.0210

Dispersion:

n/a

Pleochroism:

n/a

Occurances

Geological Setting:

In marble xenoliths within nepheline syenite breccias in an intrusive alkalic gabbro-syenite complex.

Common Associations:

Pectolite, Apophyllite, Aegirine

Common Impurities:

None

Type Locality:

Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire, Rouville Co., Québec, Canada

Year Discovered:

1987 (IMA approved 1987)

View mineral photos:

Poudretteite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Poudretteite is one of the rarest gems on Earth. It was discovered in the Poudrette quarry, Mont Sainte-Hilaire, Quebec, Canada in 1987 and more recently in 2000 in the Mogok Valley in upper Myanmar (Burma). Until the recent find in Mogok, only very tiny crystals were found at Mont Sainte-Hilaire, not large enough to be faceted. The first Mogok find initially resulted in less than a dozen faceted gems. A pale pink and colorless crystal was found that was originally identified as Scapolite but was later identified as a new discovery of Poudretteite. Poudretteite is a member of the Osumilite (Milarite) Group of minerals that includes Milarite, Poudretteite, Sogdianite and Sugilite. Poudretteite is found as colorless and pale pink to pink.
 

  
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