Titanite from Capelinha, Brazil

Titanite

Titanite or sphene is a calcium titanium nesosilicate mineral, CaTiSiO₅. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 The silicate minerals make up the largest and most important class of rock-forming Minerals They are classified based on the structure of their silicate Ion group A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Trace impurities of iron and aluminium are invariably present. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 WikipediaNaming Also commonly present are rare earth metals including cerium and yttrium. Rare earth elements and rare earth metals are according to IUPAC, the collection of seventeen Chemical elements in the Periodic table, namely Cerium (ˈsɪəriəm is a Chemical element with the symbol Ce and Atomic number 58 Yttrium (ˈɪtriəm is a Chemical element with symbol Y and Atomic number 39

Nomenclature

The use of sphene as this mineral's name has been discredited by the International Mineralogical Association Commission on New Minerals and Mineral Names (CNMMN); titanite is the approved name (see CNMMN report, p. The International Mineralogical Association ( IMA) is an international group of 38 national societies 134). Sphene was the most commonly used name until the IMA decision, and is less confusing as titanates are a class of compound with the general formula XTiO3. The name sphene continues to be publishable in peer-reviewed scientific literature, e. g. a paper by Watson et al. was published in early 2008 in the journal Cotributions to Mineralogy and Petrology. Sphene persists as the informal name for titanite gemstones. A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash

Physical properties

Titanite, which is named for its titanium content, occurs as translucent to transparent, reddish brown, gray, yellow, green, or red monoclinic crystals. In Crystallography, the monoclinic Crystal system is one of the 7 lattice Point groups A crystal system is described by three vectors. In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating These crystals are typically sphenoid (from the Greek sphenos, meaning wedge) in habit and are often twinned. The sphenoid bone (from Greek sphenoeides, "wedgelike" is a Bone situated at the base of the Skull in front of the Temporals and basilar Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly In Mineralogy, shape and size give rise to descriptive terms applied to the typical appearance or habit of Crystals The many terms used by mineralogists Possessing a subadamantine tending to slightly resinous lustre, titanite has a hardness of 5. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material 5 and a weak cleavage. Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types Its specific gravity varies between 3. Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 52 and 3. 54. Titanite's refractive index is 1. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 885-1. 990 to 1. 915-2. 050 with a strong birefringence of 0. Birefringence, or double refraction, is the decomposition of a ray of Light into two rays (the ordinary ray and the extraordinary ray 105 to 0. 135 (biaxial positive). Transparent specimens are noted for their strong trichroism, the three colours presented being dependent on body colour. Pleochroism is an Optical phenomenon in which grains of a rock appear to be different colors when observed at different angles under a Petrographic microscope. Owing to the quenching effect of iron, sphene exhibits no fluorescence under UV. Quenching refers to any process which decreases the Fluorescence intensity of a given substance Fluorescence is a Luminescence that is mostly found as an Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Some titanite has been found to be metamict. Metamictization (sometimes called metamiction) is a natural process resulting in the gradual and ultimately complete destruction of a Mineral 's Crystal lattice

Titanite is a source of titanium dioxide, TiO₂, used in pigments and is admired as a gemstone when suitably free of flaws. Titanium dioxide, also known as titanium(IV oxide or titania, is the naturally occurring Oxide of Titanium, chemical formula Ti[[oxygen For the drug referred to as "pigment" see Black tar heroin.

Occurrence

Titanite occurs in metamorphic rocks such as gneiss and schists and also in granular limestones and granite. Metamorphic rock is the result of the transformation of an existing rock type the protolith, in a process called Metamorphism, which means "change Gneiss (ˈnaɪs is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from preexisting formations that were originally The schists form a group of medium-grade Metamorphic rocks chiefly notable for the preponderance of lamellar Minerals such as Micas chlorite Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Source localites include: Pakistan, Italy, Russia, China, Brazil, Switzerland, Madagascar, the Tyrol (Austria), Canada (Renfrew County, Ontario) and the USA (California). Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and Italy (Italia officially the Italian Republic, (Repubblica Italiana is located on the Italian Peninsula in Southern Europe, and on the two largest Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld Switzerland (English pronunciation; Schweiz Swiss German: Schwyz or Schwiiz Suisse Svizzera Svizra officially the Swiss Confederation Madagascar, or Republic of Madagascar (older name Malagasy Republic) is an Island nation in the Indian Ocean off the southeastern Tyrol is a region in Western Central Europe, which included the present day Austrian state of Tyrol (consisting of North Tyrol and East Austria (Österreich ( officially the Republic of Austria (Republik Österreich Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Renfrew is a County in the Canadian province of Ontario. In 2006 the population was 97545 and county covered, giving a Population density The United States of America —commonly referred to as the California ( is a US state on the West Coast of the United States, along the Pacific Ocean.

Use as a gemstone

As a gemstone, sphene is usually some shade of chartreuse and is highly prized for its exceptional dispersive power (0. In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency 051, B to G interval) which exceeds that of diamond. In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in Unfortunately, brittleness and low hardness precludes appropriate use as a ring stone: sphene is more suited to pendants or brooches, or left unset as a collector's stone.

See also

List of minerals

References

• Webmineral data
• Mindat.org