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Titanite

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Titanite, or sphene , which means wedge, is a calcium titanium nesosilicate mineral, CaTiSiO5. Trace impurities of iron and aluminium are generally gift. Also normally present are rare earth metals which includes cerium and yttrium; calcium can be partly replaced by thorium.Titanite is a unprecedented titanium mineral that happens as an accessory mineral in granitic and calcium-wealthy metamorphic rocks. It is a minor ore of titanium and a minor gemstone called “sphene.”

Physical Properties of Titanite

 Titanite’s diagnostic homes are its crystal addiction, color, and luster. Its monoclinic crystals are regularly wedge-fashioned or tabular-fashioned. Its common shade range is yellow, inexperienced, brown, and black. Pink, orange, and crimson specimens are rare.

Chemical ClassificationCalcium titanium silicate.
ColorCommonly yellow, green, brown, black or gray. Rarely pink, red, or orange.
StreakWhite
LusterResinous to adamantine.
DiaphaneityTranslucent to transparent.
CleavageFair to good.
Mohs Hardness5 to 5.5
Specific Gravity3.4 to 3.6
Diagnostic PropertiesLuster, hardness, color, dispersion.
Chemical CompositionCaTiSiO5
Crystal SystemMonoclinic.
UsesMinor ore of titanium. Minor gemstone.

Optical Properties of Titanite

PPL
XPL
Property
Value
FormulaCaTiOSiO4
Crystal SystemMonoclinic (2/m)
Crystal HabitWedge-, and elongated rhomb-shaped crystals are common, but rounded and irregular grains are also common. Grains typically are not apparent in hand specimens.
CleavageDistinct prismatic ceavage {110} may control grain orientation. Uneven fracture. Brittle.
TwinningSimple twins may occur on {100}.
Color/PleochroismTan-brown or yellowish color. Nonpleochroic to weakly pleochroic:

 x almost colorless
y pale yellow
z brownish

Optic SignBiaxial (+)
2V20-40°
Optic OrientationX /\ a=-6° to -21°
Y=b
Z /\ c=36-51°
Refractive Indices
alpha =
beta =
gamma =
1.843-1.950
1.970-2.034
1.943-2.110
Max Birefringence0.100-0.192
Elongationcannot be easily determined
ExtinctionBecause of high dispersion, some grains do not extinguish completely.
Dispersion r > v
Distinguishing FeaturesVery High Relief. Extreme birefringence; same brownish color in plane and crossed polars. Diamond/wedge-shaped crystal habit
OccurrenceTitanite is a common accessory in many igneous and metamorphic rocks, of which it can be the dominent Ti-bearing contituent. Titanite also occrs as detrital grains in the heavy mineral fraction of clastic sediments.
EditorsSarah Pistone (’06), Janelle McAtamney (’07), Molly Peek (’18)
SourcesPhilpotts, Anthony R., 1989. Petrogrophy of Igneous and         Metamorphic Rocks. Waveland Press, Inc.: Prospect Heights,        Illinois. 61 p.
Nesse, William D., 2000. Introduction to Mineralogy. Oxford         University Press: New York, NY. 322 p.
MacKenzie W.S., and Guilford C., 1980. Atlas of rock-forming         minerals in thin section. Halsted Press: New York, NY. 97p.

Chemical Composition of Titanite

Titanite has a chemical composition of CaTiSiO5 and every now and then includes uncommon earth factors which include cerium, niobium, and yttrium. It can contain other factors together with aluminum, chromium, fluorine, iron, magnesium, manganese, sodium, and zirconium.

Occurrence of Titanite

Titanite occurs as a common accessory mineral in intermediate and felsic igneous rocks and associated pegmatites. It also occurs in metamorphic rocks such as gneiss and schists and skarns. Source localities include: Pakistan; Italy; Russia; China; Brazil; Tujetsch, St. Gothard, Switzerland;Madagascar; Tyrol, Austria; Renfrew County, Ontario, Canada; Sanford, Maine, Gouverneur, Diana, Rossie, Fine, Pitcairn, Brewster, New York and California in the US.

Uses of Titanite

Titanite is a source of titanium dioxide, TiO2, utilized in pigments.

As a gemstone, titanite is normally some coloration of chartreuse, but can be brown or black. Hue depends on Fe content, with low Fe content causing green and yellow colorings, and high Fe content material inflicting brown or black colorations. Zoning is regular in titanite. It is prized for its outstanding dispersive power  which exceeds that of diamond.Jewelry use of titanite is restricted, each because the stone is uncommon in gem pleasant and is rather gentle.

Cite this article as: Geology Science. (2019). Titanite. [online] Available at: http://geologyscience.com/minerals/titanite/ [9th December 2019 ]
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