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| Titanite was
named in 1795 by Martin Klaproth for its high TITANium
content (18%). The name Sphene was introduced in 1801
by Rene Just Haüy and is from the Greek word sphenos
for wedge referring to its characteristic wedge-shaped
crystals.
| Discovered
in 1795; IMA
status: Valid (pre-IMA; Grandfathered) |
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Chemistry
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Chemical
Formula: |
CaTiSiO5
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Calcium
Titanium
Silicate |
Molecular
Weight: |
197.76 gm
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Composition: |
Calcium |
19.25 % |
Ca |
26.94 % |
CaO |
|
La,Ce,Pr,Nd,Sm |
3.64 % |
RE |
4.25 % |
REE2O3 |
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Titanium |
18.16 % |
Ti |
30.29 % |
TiO2 |
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Aluminum |
2.73 % |
Al |
5.16 % |
Al2O3 |
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Iron |
1.41 % |
Fe |
2.02 % |
Fe2O3 |
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Silicon |
14.20 % |
Si |
30.38 % |
SiO2 |
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Oxygen |
39.64 % |
O |
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Fluorine |
0.96 % |
F |
0.96 % |
F |
|
— |
—
% |
F |
-0.40 % |
-O=F2 |
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|
100.00 % |
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99.60 % |
= TOTAL OXIDE |
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Classification
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Mineral
Classification: |
SILICATES (Germanates)
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Strunz 8th
Ed. ID:
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8/B.12-10
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Nickel-Strunz 10th
Ed. ID:
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9.AG.15
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9 : SILICATES (Germanates)
A : Nesosilicates G :
Nesosilicates with additional anions; cations in > [6] +- [6] coordination
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Related
to: |
Titanite Group
(structurally related to Tilasite Group).
Titanite - Malayaite Series. The titanium analogue of
Malayaite and Vanadomalayaite. Isostructural with Durangite and Tilasite.
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Members
of Group: |
Titanite Group:
Lederite (of Shepard),
Malayaite, Natrotitanite, Titanite, Vanadomalayaite
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Varieties: |
Chromian Titanite,
Eucolite-Titanite, Greenovite, Grothite, Keilhauite,
Lederite (of Shepard), Stanniferous Titanite, Yttrian Titanite
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Synonyms: |
Aspidelite,
Castellite, Ligurite, Menakerz, Sphen, Sphene, Titanite (of Klaproth)
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Crystal
Data
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Crystallography:
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Monoclinic
- Prismatic
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Crystal
Habit:
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Crystals
wedge-shaped, flattened or prismatic by extension along
[110], to 16 cm; compact, massive
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Twinning:
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On
[100], contact and penetration; less commonly lamellar
on [221]
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Physical
Properties
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Cleavage: |
Distinct
on [110], Imperfect on [100] and [112];
parting due to twinning on [221]
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Fracture: |
Sub-Conchoidal
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Tenacity:
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Brittle
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Moh's
Hardness: |
5.0 - 5.5 |
Density:
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3.48 - 3.60 (g/cm3)
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Luminescence:
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None
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Radioactivity:
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Mild;
GRapi = 3,805.77 (Gamma Ray American Petroleum Institute Units)
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Other: |
May
be metamict.
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Optical
Properties
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Color: |
Colorless,
Reddish Brown, Red, Yellow, Green, Gray, Black
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Transparency: |
Transparent
to Translucent, Opaque |
Luster: |
Adamantine
to Resinous |
Refractive
Index: |
1.843
- 2.110 Biaxial ( + ) |
Birefringence: |
0.100 - 0.160 (high) |
Dispersion: |
Extreme; r > v |
Pleochroism: |
Visible;
distinct when deeply colored; X
= nearly colorless; Y
= yellow to green; Z
= red to yellow-orange |
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Occurances
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Geological
Setting: |
A
common accessory mineral in intermediate and felsic
plutonic rocks, pegmatites, and alpine veins. In gneisses,
schists, and some skarns; rarely detrital. |
Common
Associations: |
Albite,
Allanite, Apatite, Biotite, Calcite, Chlorite, Diopside,
Epidote, Ilmenite, Magnetite, Monazite, Nepheline |
Common
Impurities: |
Fe,
Y, Mn, Al, Ce, Sr, Na, Nb, Ta, Al, Mg, V, F, Zr, Sn
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Type
Locality: |
Titanite occurrence, Hauzenberg, Lower Bavaria, Bavaria, Germany
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Year
Discovered: |
1795
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View
mineral photos: |
Titanite
Mineral Photos and Locations |
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More
Information
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Mindat.org
Webmineral.com
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Titanite
(also known as Sphene) is a beautiful gem with high
dispersion, high refractive index (greater than Diamond), high birefringence
and intense red, green and yellow colors. Unfortunately,
it also has low hardness and is brittle so not recommenced
for jewelry. Titanite is typically slightly to moderately
included and clean gems are particularly rare and beautiful.
Titanite may be mildly radioactive as defined
in 49
CFR 173.403
(greater than 70 Bq/gram) due to the presence of the
Rare Earth Elements (REE) Cerium (Ce), Lanthanum (La),
Neodymium (Nd), Praeseodymium (Pr) and
Samarium (Sm).
Titanite may also be metamict. This means that the original
crystal structure has been broken down and turned amorphous
due to radiation damage. An intensly vivid green, chromium
(Cr) rich variety of Titanite exists called Chromian Titanite. The
main source of Chromian Titanite is the Saranovskii Mine, Saranovskaya Village, Gornozavodskii area,
Permskaya Oblast', Middle Urals Region, Russia.
Notable
occurances of gemmy crystals of Titanite include Gilget and Badakhshan Provinces, Afghanistan;
Pi~no Solo. From Campo do Boa, Capelinha, Minas Gerais,
Brazil; Antsiranana and Tuléar Provinces, Madagascar;
Skardu District, Baltistan, Northern Areas, Pakistan;
and Subpolar Ural Mountains, Russia.
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(Sphene) gems for sale:
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