Titanite


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titanite

[′tīt·ən‚īt]
(mineralogy)

Titanite

 

(also sphene), a silicate mineral having an isolated arrangement of SiO4 tetrahedrons and a chemical formula of CaTiO[SiO4]. Titanite contains admixtures of Fe2+ and Fe3+ and has up to 12 percent (Ce, Y)2O3 (in keilhauite, a variety of titanite), Mn, Sn, Nb, and Cr. Crystallizing in the monoclinic system, titanite generally forms separate crystals in the form of flattened prisms having a characteristic wedge-shaped cross section. The mineral also occurs as granular aggregates.

Titanite can be yellow, brown, or green; sometimes it is black or reddish. It has an adamantine luster, a hardness on Mohs’ scale of 5–6, and a density of 3,300–3,600 kg/m3. Titanite is widely distributed as an accessory mineral in igneous rocks; it occurs most often in alkalic rocks but is sometimes found in metamorphic gneisses and other rocks and in hydrothermal formations. In significant accumulations, titanite is a source of Ti.

References in periodicals archive ?
It presents inclusions of titanite and epidote, which are oriented in the same direction of the external foliation.
Bocabec Charles mineralogical, textural, Hanson geochemical match and temporal-logistical fit Digdeguash McGrattan operation began too late Lake Spinney North operation began too late, too fresh, too much olivine Spinney South operation began too late, too fresh, too much olivine Second Frost mineralogical and Falls Mountain textural mismatch George mineralogical and Maxwell textural mismatch Stein Lake Glenelg Road titanite present, too leucocratic Russells Ridge titanite present, grain size Stuart/ workings too small, texture too Chickahominy variable Townsend workings too small, too altered, not operating in 1912 St.
The rhyolite sheets are sparsely porphyritic, at places banded, and composed of perthite, quartz, albite, sodic amphibole, aegirine-augite, opaque oxide and titanite.
The most common were apatite, titanite, ilmenite, rutile, and Fe-oxyhydroxides (forming very small grains (inclusions) of < 0.
Especially since World War II, the pegmatites of the state of Minas Gerais have yielded some of the world's finest specimens of topaz, chrysoberyl, euclase, elbaite, and beryl (in all of its colored varieties); phosphate-rich pegmatites of the same state have furnished the world's finest specimens of brazilianite, beryllonite, eosphorite, hydroxylherderite, amblygonite and more; complex pegmatites of other kinds have provided cassiterite, xenotime, monazite and several rare-earth species; Brazilian specimens of titanite, phenakite, fluorapatite, kyanite, scheelite, spessartine and bertrandite are among the world's very best.
Petrographic and SEM-EDS analysis resulted in the following observations: (1) Titanite is present in both layer types: titanites in amphibole layers contain inclusions of amphibole, and titanites in epidote layers contain inclusions of epidote.
A mixture of plagioclase (albite; 30%) and amphibole (hornblende; 65%) dominates the matrix with presence of minor (5%) epidote, titanite, quartz and garnet.
The fully enclosed attached shelter has a patented Titanite geodesic support structure designed to withstand sub-zero to tropical/desert weather and wind conditions.