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Taaffeite (Magnesiotaaffeite-2N'2S)
Current inventory:  2 gems
 

Taaffeite

  
Taaffeite was originally named after Count Edward Charles Richard Taaffe (1898 - 1967), a Bohemian-Irish gemologist, who discovered the first specimen in 1945 in Niriella Village, Ratnapura, Sabaragamuwa province, Sri Lanka.

Discovered in 1945 (1951);   IMA status: Valid (approved 1982)

 

Chemistry

 

 

Chemical Formula:

Mg3Al8BeO16

 

Magnesium Aluminum Beryllium Oxide

Molecular Weight:

553.77 gm

Composition:

Magnesium

13.17 %

Mg

21.83 %

MgO

 

Beryllium

1.63 %

Be

4.52 %

BeO

 

Aluminum

38.98 %

Al

73.65 %

Al2O3

 

Oxygen

46.23 %

O

 

 

 

 

100.00 %

 

100.00 %

= TOTAL OXIDE

 

 

Classification

   

   

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/B.07-20

Nickel-Strunz 10th Ed. ID:

4.FC.25

 

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
C : Hydroxides with OH, without H
2O; corner-sharing octahedra

Related to:

Taaffeite Group.

Members of Group:

Taaffeite Group: Ferrotaaffeite-6N'3S (Perhmanite), Magnesiotaaffeite-2N’2S (Taaffeite),  Magnesiotaaffeite-6N’3S (Musgravite)

Varieties:

None

Synonyms:

Bemagalite, Magnesiotaaffeite-2N'2S, Taaffeite, Taprobanite

 

 

Crystal Data

   

   

Crystallography:

Hexagonal - Dihexagonal Pyramidal

Crystal Habit:

Crystals are hexagonal, pyramidal or flattened, to 2 cm, may be intergrown with Nigerite or Hogbomite; in fine-grained aggregates. Typically found as tumbled stones in gem gravels.

Twinning:

Possible on {0001}

 

 

Physical Properties

   

 

Cleavage:

Fair on {001}

Fracture:

Irregular/Uneven, Conchoidal

Tenacity:

Brittle

Moh's Hardness:

8.0 - 8.5

Density:

3.605 - 3.613 (g/cm3)

Luminescence:

None

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

Color:

Mauve, Lilac, Pink, Violet Red, Red, Brown, deep to pale Grayish Purple, Blue, Greenish, pale Beige-Gray, may be nearly Colorless.

Transparency:

Transparent to Translucent

Luster:

Vitreous

Refractive Index:

1.717 - 1.736  Uniaxial ( - ); may be anomalously Biaxial

Birefringence:

0.0550

Dispersion:

n/a

Pleochroism:

E= yellow rose; 0 = carmine red (for a deep red example)

 

 

Occurances

   

   

Geological Setting:

In gem gravels (Sri Lanka); in skarns at the contact between dolostones and limestones with beryllium-bearing granite (Hsianghualing Ridge, China); in spinel-phlogopite schists (Mt. Painter, Australia).

Common Associations:

Spinel, Apatite, Phlogopite, Zircon, Garnet, as inclusions (Sri Lanka); Hsianghualite, Chrysoberyl, Phenakite, Zinnwaldite, Cancrinite, Fluorite, Spinel, Calcite (Hsianghualing Ridge, China).

Common Impurities:

None

Type Locality:

Niriella Village, Ratnapura, Sabaragamuwa Province, Sri Lanka

Year Discovered:

1945; identified as a new mineral in 1951; IMA approved in 1982

View mineral photos:

Taaffeite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Taaffeite (p
ronounced TARF-ite) is one of the rarest gems. It was originally thought to be mauve colored Spinel but was found to be doubly refractive. This is impossible in the isometric crystal system of Spinel. Except for double refraction, Taaffeite has properties that are almost identical to Spinel such as hardness, density and index of refraction. Taaffeite reacts to most gemological tests like mauve colored Spinel, but can be distinguished from Spinel by its birefringence. It is found in shades of pink, mauve or grayish violet and colorless. The most notable occurance of Taaffeite is in the alluvial deposites in Sri Lanka. Taaffeite has also been found in Myanmar (Burma), Tanzania and Långban, Filipstad, Värmland, Sweden.

Taaffeite was originally named after Count Edward Charles Richard Taaffe (1898 - 1967), a Bohemian-Irish gemologist, who discovered the first specimen. It has recently been renamed Magnesiotaaffeite-2N’2S as a method of clarifying the complexity of the compositions of Taaffeite group minerals including Musgravite, Perhmanite and Taaffeite and the influences of the minerals Spinel and Nolanite on them. The Taaffeite group is redefined for minerals composed of Spinel and modified Nolanite modules. The modified Nolanite module has the composition BeTM4O8. If the Spinel module is dominated by the Spinel component, MgAl2O4, the prefix ‘magnesio’ is used. If the Spinel module is dominated by the Hercynite component, FeAl2O4, the prefix ‘ferro’ is used.

So, according to the new nomenclature accepted by the IMA (International Mineralogical Association), Taaffeite has become Magnesiotaaffeite-2N’2S, as it is composed of two modified Nolanite modules (2N) and two Spinel modules (2S). Correspondingly, Musgravite has become Magnesiotaaffeite-6N’3S and Perhmanite has become Ferrotaaffeite-6N’3S. Taaffeite is now an IMA approved name for the group of minerals containing Musgravite (Magnesiotaaffeite-6N’3S), Perhmanite (Ferrotaaffeite-6N’3S) and Taaffeite (Magnesiotaaffeite-2N’2S). The name Musgravite has been relegated to trade name status. However, I suspect that the names Taaffeite and Musgravite will continue to be used in the gem trade as the individual gem names.
 

  
Taaffeite gems for sale:

Taaffeite-003

Gem:

Taaffeite

Stock #:

TAAF-003

Weight:

0.0310 ct

Size:

1.98 x 2.19 x 1.21

Shape:

Trillion

Color:

Colorless

Clarity:

Flawless

Origin:

Mogok, Myanmar (Burma)

Treatment:

None

Price:

$140.00    [ Make an offer ]

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Taaffeite Certificate

An exceptionally rare gem that is well faceted and of a relatively affordable size. This gem includes the pictured certification from the Gem and Jewelry Institute of Thailand (GIT).


Taaffeite-002

Gem:

Taaffeite

Stock #:

TAAF-002

Weight:

0.2080 ct

Size:

3.14 x 3.06 x 2.41 mm

Shape:

Square

Color:

Colorless

Clarity:

Eye Clean - SI

Origin:

Mogok, Myanmar (Burma)

Treatment:

None (natural)

Price:

$120.00    [ Make an offer ]

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Taaffeite-002

This very rare gem is from a recent find of colorless crystals in Mogok, Myanmar (Burma).


Taaffeite-001

Gem:

Taaffeite

Stock #:

TAAF-001

Weight:

1.3935 ct

Size:

6.68 x 5.72 x 4.56 mm

Shape:

Oval

Color:

Lavender/Mauve

Clarity:

Eye Clean - SI

Origin:

Sri Lanka

Treatment:

None (natural)

Price:

SOLD

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Taaffeite-001

An extremely rare gem from Sri Lanka. This gem comes from the collection of Murray Burford, famed gemologist from Canada, known for investigating and identifying rare gems from Thailand, Myanmar (Burma), Sri lanka and more recently from Tanzania and Madagascar.


 


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