Titanite is a calcium-titanium silicate mineral with the formula CaTiSiO5. Rare earth elements such as thorium, cerium, and yttrium are sometimes present in Titanite in minor quantities. It can contain other elements such as aluminum, chromium, fluorine, iron, magnesium, manganese, sodium, and zirconium.
Titanite is frequently called by the name Sphene, which was used for this mineral before 1982. In 1982, the IMA adopted the official name Titanite and discredited Sphene. The name Sphene is still frequently used, especially in Europe. Titanite is named for its titanium content. Its alternate name, Sphene, is named from the Greek term “sphenos”, which means wedge, in allusion to the typical wedge-shaped crystals exhibited by this mineral.
Titanite is known for its high luster and dispersion rate. This results in transparent Titanite crystals being brilliant and opaque Titanite being highly reflective. It is also pleochroic, with different transparent crystals exhibiting different hues when viewed at different angles. Sphene continues to be the name used for this mineral in the gem and jewelry industries. It is a minor gemstone that is popular with collectors because of its high dispersion. Sphene is one of the few minerals with a dispersion higher than diamond. The dispersion of diamond is 0.044, while the dispersion of sphene is 0.051. Specimens of sphene with high clarity can display a strong, colorful fire when light is passed through them.
Color is light to dark brown, orange, yellow, yellowish-green, olive-green, emerald-green, greenish-brown. Rarely white, colorless, gray, pink, or purple. May have color zones with lighter to darker browns. Iron has a strong influence on the color of Titanite. Small amounts of iron darken the color. Yellow and green specimens have a low iron content, while brown and black specimens have a higher iron content.
Titanite belongs to the Monoclinic Crystal System, Prismatic Crystal Class. Hardness is 5 – 5.5 on the Moh’s Scale. Luster is resinous to adamantine. Crystals are usually transparent to translucent.
This mineral is a rare titanium mineral that occurs in metamorphic rocks such as marble, gneiss, schist, and skarns, and especially in contact zones. Also, in hydrothermal replacement deposits, in altered diabase and granite, and in nepheline syenite pegmatites. Crystals are usually found as sharply angled, wedge-shaped crystals. Crystals may be in flattened tabular form, in prismatic crystals with pointed terminations, and in complex dipyramidal crystals. Twinning is as common as repeated twins. It may also be grainy, massive, and in rounded waterworn floater crystals. Crystals are sometimes striated or naturally etched.
Varieties of Titanite:
Chrome Titanite – Emerald-green, chromium-rich variety
Greenovite – A pink to red, manganese-rich variety of Titanite.
Grothite – Describes either an aluminum-bearing Titanite, or a form of Titanite containing Titanite containing yttrium or cerium.
Keilhauite – A rare-earth bearing Titanite rich in yttrium.
Xanthitane – Yellow, earthy Anatase pseudomorph after Titanite.
Triclinic Titanite – a variety of Titanite with triclinic symmetry.
Noteworthy Localities
The type locality of Titanite is Hauzenberg, Passau District, Lower Bavaria, Bavaria, Germany. Triclinic Titanite has only been found in Heftetjern pegmatite, Tørdal, Drangedal, Vestfold og Telemark, Norway.
Exceptionally large and gemmy green Titanite crystals come from several alpine-type deposits in the Skardu district, Gilgit-Baltistan, Pakistan, especially at the Shigar and Tormiq Valleys.
The alpine cavities of the European Alps in Austria, Italy, and Switzerland have produced many fine Titanite crystals. While most localities have only produced small crystals, several localities are noted for large, well-formed crystals. In Austria, gemmy, olive-green Titanite crystals have come from the Felbertal and Habachtal, Hohe Tauern, Salzburg; large green and brown crystals from the Zillertal, North Tyrol; and yellowish-green crystals with contrasting white Albite and Quartz from Törlkopf and Mallnitz, Carinthia. In Switzerland, twinned pointy Titanite crystals, sometimes elongated, come from Tujetsch, Grischun; and green as well as a rare violet Titanite comes from the St Gotthard Massif, Ticino.
In Russia, an Emerald-green “Chrome Titanite” is described from the Saranovskii Mine, Sarany, in the Ural Mountains, and twinned dark brown crystals from the Dodo Mine, Saranpaul, Khanty-Mansi Okrug.
In Africa, lustrous brown and green Titanite crystals are found in Imilchil, Morocco; and olive-green, transparent, flattened twins come from Ankarafa, Antsiranana Province, Madagascar.
Brazil has produced exceptionally large, gemmy, olive-green green crystals that are often twinned at Capelinha, Minas Gerais.
In the United States, greenish-brown Titanite crystals, sometimes coated with Chlorite, have come from the Acushnet Quarry, Bristol County, Massachusetts. Sharp brown crystals with highly reflective surfaces are found in New York at Amity, Orange County; as well as several localities in the Adirondacks such as Rossie and Oxbow, St. Lawrence County; and Natural Bridge, Lewis County. Small yellow transparent crystals are classics from the Tilly Foster Mine, Brewster, Putnam County, New York.
In Canada, large, sharp, dark brown crystals have come from Ontario at Eganville and Sebastopol Township, Renfrew County, and at Wilberforce and Bear Lake, Haliburton County.
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By Bill Jones, Sidewinder Minerals
