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| 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) |
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Chemistry
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Chemical
Formula: |
Mg3Al8BeO16
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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 |
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|
|
100.00 % |
|
100.00 % |
= TOTAL OXIDE |
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Classification
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Mineral
Classification: |
Oxides
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Strunz 8th
Ed. ID:
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4/B.07-20
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Nickel-Strunz 10th
Ed. ID:
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4.FC.25
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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 H2O; corner-sharing octahedra
|
Related
to: |
Taaffeite Group.
|
Members
of Group: |
Taaffeite Group:
Ferrotaaffeite-6N'3S
(Perhmanite), Magnesiotaaffeite-2N’2S
(Taaffeite),
Magnesiotaaffeite-6N’3S
(Musgravite)
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Varieties: |
None
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Synonyms: |
Bemagalite,
Magnesiotaaffeite-2N'2S,
Taaffeite, Taprobanite
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Crystal
Data
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Crystallography:
|
Hexagonal - Dihexagonal
Pyramidal
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Crystal
Habit:
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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.
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Twinning:
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Possible
on {0001}
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Physical
Properties
|
|
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Cleavage: |
Fair
on {001}
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Fracture: |
Irregular/Uneven,
Conchoidal
|
Tenacity:
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Brittle
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Moh's
Hardness: |
8.0
- 8.5
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Density:
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3.605 - 3.613 (g/cm3)
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Luminescence:
|
None
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Radioactivity:
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Not
Radioactive
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Optical
Properties
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Color: |
Mauve,
Lilac, Pink, Violet Red, Red,
Brown, deep to pale Grayish Purple, Blue, Greenish,
pale Beige-Gray, may be nearly Colorless.
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Transparency: |
Transparent
to Translucent |
Luster: |
Vitreous
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Refractive
Index: |
1.717 - 1.736 Uniaxial
( - ); may be anomalously Biaxial |
Birefringence: |
0.0550
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Dispersion: |
n/a
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Pleochroism: |
E=
yellow rose; 0 = carmine red (for a deep red
example)
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Occurances
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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 |
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More
Information
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|
Mindat.org
Webmineral.com
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Taaffeite (pronounced 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.
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Taaffeite
gems for sale:
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Gem:
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Taaffeite |
Stock
#:
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TAAF-003 |
Weight:
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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. |
|
|
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).
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Gem:
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Taaffeite |
Stock
#:
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TAAF-002 |
Weight:
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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. |
|
|
This
very rare gem is from a recent find
of colorless crystals in Mogok,
Myanmar (Burma).
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Gem:
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Taaffeite |
Stock
#:
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TAAF-001 |
Weight:
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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. |
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|
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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