Photo of Titanite in Processed & Rough Form
Titanite is a mineral with a hardness of 5 out of 10 on the Mohs scale of mineral hardness [?]. These Monoclinicly structured gems are made of calcium titanium silicate, their full chemical compound being CaTiSiO5.
Titanite is a very rare calcium titanium silicate that is an important ore of titanium. It is also called Sphene. Its crystals are very rare, brilliant, and sparkles like diamond.
It appears as crystals that are prisms with pyramid tips, or stubby, wedge-shaped, flattened crystals, or tabular and platy. There are also titanite crystal twins that have grown side by side or interpenetrated, or in granular aggregates.
Color varies from white to yellow-green with a chartreuse hue, dark brown or black. In rare cases they may be colorless or pink.
It is hard, heavy and has distinct cleavage. The crystals are brilliant but comparatively soft. It is transparent or translucent with adamantine to resinous luster. Some deeply colored varieties display marked trichroism, and will exude a range of colors when light is beamed on it. Other varieties of titanite/sphene may be opaque. It dissolves partially in hydrochloric acid, and completely in sulfuric acid. If hydrogen peroxide is added, the solution turns yellow (titanium). It fuses fairly easily, giving dark yellow glass.
Titanite is an accessory mineral common in many acid and intermediate igneous rocks, and in gneisses, mica schists, and amphibolites. It also occurs in limestones that have had contact with magmatic rock, and in low-temperature hydrothermal veins. The largest crystals are found in rodingites and nepheline syenite pegmatites. It is also found in alluvial sand areas.
Deposits of large titanite masses occur in the Kola Peninsula, the industrialized nuclear-intensive region in northwestern Russia, right on the Arctic, where over 300 kinds of minerals have been discovered. Emerald-green specimens of titanite have been found in the Urals.
Fine crystals are found in the metamorphic dolomites in the Binnental (Switzerland) and at Renfrew, Ontario (Canada), in granite and gneiss lithoclases in the Gotthard region (Switzerland) and the Zillertal (Tyrol, Austria) and in the rodingites in Val d'Ala (Turin) and the Gruppo di Voltri (Genoa, Italy).
It occurs in the USA in New York and New Jersey. In Italy it is also found at Alpe Devero (Domodossola), in Val Malenco (Sondrio), at Prali in Cal Germanasca (Turin), and in pyroclastic material spewed by Mount Vesuvius and the volcanoes of Lazio. Pink titanite occurs at Saint-Marcel in Val d'Aosta (Italy), associated with other manganese minerals (diopside, piedmontite, etc.) Transparent orange sphene has been found in Myanmar.
Varieties of titanite/sphene include grothite, and alshedite - a variety of titanite, or sphene, containing yttrium, named after the parish of Alsheda in Sweden.
Titanite/sphene can be confused with many other gems.
Titanites crystal structure is Monoclinic. Monoclinic crystal systems are formed into vectors of varying lengths.What causes Titanite's exceptional dispersion?
The high dispersion (0.051) results from titanium content in the crystal structure. This creates stronger color separation than diamond, producing distinctive fire in properly cut specimens.
How do rare earth elements affect coloration?
Incorporation of rare earth elements creates color variations from green to brown to yellow. Chromium substitution produces emerald-green varieties, while iron content typically results in brown coloration.
What explains the strong pleochroism?
Crystal structure asymmetry creates pronounced pleochroism, showing distinct color variations along different crystallographic axes. This optical property requires specific orientation during cutting.
How do formation conditions affect crystal habit?
Titanite develops in various geological environments, from metamorphic to igneous formations. Growth conditions determine crystal habit, ranging from wedge-shaped to tabular forms. Contact twins are common in certain localities.
What analytical methods confirm identification?
Raman spectroscopy and X-ray diffraction provide definitive identification. Optical properties, including high birefringence and refractive indices, offer additional diagnostic criteria.
Why is radioactivity common in specimens?
Natural radioactivity occurs due to uranium and thorium substitution in the crystal structure. This can lead to metamict state development, affecting optical properties and structural integrity over time.
What determines gem-quality material?
Gem-quality specimens require high transparency, minimal inclusions, and strong color saturation. Structural integrity and absence of metamict alteration are crucial for faceted stones.
The specific gravity [?] for Titanite is 3.53, its refractive index [?] is 1.84-2.03, and its double refraction [?] is 0.12.
History
Sphene derives its name from the Greek word "sphen" meaning "wedge," because the crystals are commonly wedge-shaped. The element titanium was named after the Titans, the mythical sons of the Earth.
Industrial Usages
Large masses of titanite/sphene are processed as an ore of titanium, which in turn is a strong material that can withstand and resist several wearing-down factors like corrosion, extreme temperatures, corrosion, cracks, and fatigue. Titanite is also a source of titanium oxide, which is used as a pigment in paint.
The mineral is not widely used in jewellery, because the clear, green, yellow or brownish stones used as gems are rare. And because of its low hardness, it cannot take a lot of knocks, so it is usually set in earrings and pendants.
The clear and attractive colored varieties have a very intense fire that displays multiple colors under direct light, and are cut as cabochons or faceted into very valuable gems, and are very popular with both collectors and scientists. Dark-colored natural stones are made lighter by heat treatment.
You May Also Like...
Rutile: Rutile with anatase and brookite is a trimorph of titanium oxide in the Rutile group. It forms characteristic slender prismatic striated lengthways, variably terminated and often geniculate twinned crystals of the tetragonal system. Elbow- and heart-shaped (geniculated) twin crystals are common. It is hard, heavy, fragile, with perfect cleavage. It has a metallic to adamantine lustre and is (read full)
Benitoite: Benitoite is a rare gemstone / mineral that fluoresces when lit by black lights. It gets its name from San Benito County, California where it was first found. This gem is almost always blue (it was originally thought to be a sapphire) but also has variations in purple, pink, and clear. Gem prices seem to fluctuate but a few hundred dollars per half ct is common. Why so expensive? The quality gem (read full)
Rose Quartz: Rose quartz is a usually cloudy, translucent, delicate pale pink, deep pink, rose-red to quasi-white and often veined variety of Quartz. Also known as pink quartz , rose quartz may occur more often as anhedral masses or rarely as crystals which often reach quite large sizes. Rose quartz almost always occurs in pegmatites in massive crystalline bodies which do not show crystal faces. These larg (read full)
Andradite: Andradite is a name given to members of the garnet that contain manganese and titanium. The 3 types Andradite are..1.)Demantoid, 2.)Melanite, and 3.) Topazolite Demantoid-the word means diamond like. It is yellow green to green in color and is the most valuable of the 3 types. Demantoid is soft enough that older gems will have facet edges that are slightly worn. Largest deposits have been found i (read full)
Shell: Shell is the hard, protective, outer layer covering of certain creatures found in saltwater or freshwater, such as mollusks, snails, and turtles. This layer consists of calcium-carbonate and chitin, secreted by the soft tissue mantle of most mollusks. The inner surface of the shell is made from smooth nacre which covers the mantle. Shell is used as inexpensive material for various purposes in je (read full)
