Where can rutile be found frequently

Rutile

Author: Torsten Purle (steine-und-minerale.de) | Last update: 04.05.2021


Rutile - properties, formation and use

English: rutile | French: rutile


Rutile, Roter Schörl and Nadelstein

The mineral rutile was marketed under the name Rother Schörl or Nadelstein until 1800 - referring to the shape of the crystals, which are reminiscent of fine needles and the visual resemblance to rod-like Schörl.
Over time, however, it turned out that rutile is not a Schörl variety.
The current name, derived from Latin, rutile, is due to the mineralogist Abraham Gottlob Werner (1749 to 1817), as the geologist and paleontologist Friedrich August Quenstedt wrote in 1863: "The right Werner'sche Name refers to the red color, rutilus."


Table of Contents


Properties of rutile

From a chemical point of view, rutile is titanium dioxide (TiO2), just like anatase and brookite, so that rutile is assigned to the mineral class of oxides.

The color of rutile is not just red. The crystals can also be yellow, brownish yellow, reddish brown, purple, blue or black in color, as in the case of the rutile variety nigrin.
The color names of rutile in the works of historical mineralogists sound almost poetic. Georg Adolf Suckow (1751 to 1813, mineralogist) characterizes the color of rutile as "dark blood red, also cherry-hyacinth and brownish-red, and sometimes reddish-brown". His colleague Johann Georg Lenz (1748 to 1832) writes in 1794 that rutile is of "kermesin - partly blood and peach-blood-red color".
Despite the variety of colors of rutile, the line color is yellow-brown, i.e. if rutile is painted over an unglazed porcelain plaque, a yellow-brown powdered abrasion appears.

Rutile crystallizes following the tetragonal crystal system and forms long prismatic, bipyramidal crystals, which often grow together to form twins or multi-linges. The aggregates are fine-needle, radial, granular or coarse.

The sheen of rutile is metallic to diamond with transparent to translucent transparency. The fracture of the mineral is shell-like and uneven, the cleavage is completely evident.

The hardness of rutile is 6 to 6.5 on the 10-point scale of the hardness of minerals according to the mineralogist Friedrich Mohs (1773 to 1839); the density of rutile is 4.18 to 4.25 g / cm3.




Formation and distribution of rutile

Rutile can be formed in a number of ways. On the one hand, rutile is of magmatic origin and crystallizes out of fluid-rich solutions; on the other hand, the formation of rutile crystals can be traced back to metamorphic, in particular contact metamorphic, processes. The mineral is sometimes also contained in sedimentary rocks due to its high resistance to weathering.

Rutile is contained in many rocks such as mica schist, gneiss or granite as a mixture or mineral component.
In addition, rutile can grow into crystals in the course of its formation, such as often in ruby, rock crystal, almandine and rose quartz.
Above all, overlapping rutile needles in sapphire and ruby ​​produce visually attractive effects in the form of a six-pointed star (so-called asterism).

The natural occurrences of rutile are accompanied by a number of other minerals, including, for example, chlorite, apatite, quartz, calcite, albite, kornerupine, anatase, brookite, titanite, pyrophyllite, ilmenite and hematite.

Significant finds of rutile were in Kragerö / Norway, Greenland, Tyrol, Styria / Austria, Ticino, Tavetsch, Graubünden / Switzerland, Italy, Urals / Russia, Transylvania / Romania, Sierra Leone, Nigeria, Namibia, Bahia / Brazil, Virginia, Georgia , Carolina, Connecticut, Massachusetts, Vermont, New York / USA.


Use and importance of rutile

Due to the up to 60% titanium content, rutile is of economic importance for the extraction of the transition metal titanium. In addition, rutile is used in dye solar cells.

But rutile is also a sought-after mineral in the jewelry industry, insofar as the stone is processed into jewelry. Above all, clear crystals with enclosed rutile needles are in demand or minerals in which asterism is caused as a result of embedded rutile needles.




Detection of rutile

Rutile is a very resistant mineral that is not soluble in acids. The pleochroism of rutile appears in yellow to reddish brown.


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miscellaneous

In addition to real rutile, imitations can also be bought on the gemstone market. The name of the stones grown in the laboratory: diamontite or titania. However, the manufacture of the artificial crystals was not intended to create a duplicate of rutile. Rather, the developers wanted to create an imitation diamond.


See also:
⇒ Minerals and precious stones as an investment
⇒ Ore - metal containing minerals and rocks
⇒ Slag - by-product of ore abandonment


Swell:
⇒ Lenz, J. G. (1794): Rother Schörl. IN: Attempt to provide a complete guide to the knowledge of minerals
⇒ Ludwig, C. F. (1803): Rutile. IN: Handbook of Mineralogy according to A. G. Werner
⇒ Suckow, G. A. (1804): Titanschörl. IN: The beginnings of mineralogy. Volume 2
⇒ Mohs, F. (1804): Rutile. IN: Mr. Jac.-Friedr. of the Null Mineralien-Kabinet, described in a systematic manner, and made usable as a manual for oryctognosy. Volume 2
⇒ Quenstedt, J. G. (1863): Titan ores. Rutile. IN: Handbook of Mineralogy
⇒ Pellant, C. (1994): Stones and Minerals. Ravensburger nature guide. Ravensburger Buchverlag Otto Maier GmbH
⇒ Bauer, J .; Tvrz, F. (1993): The Cosmos Mineral Guide. Minerals rocks precious stones. An identification book with 576 color photos. Gondrom Verlag GmbH Bindlach
⇒ Korbel, P .; Novak, M. and W. Horwath (2002): Mineralien Enzyklopädie, Dörfler Verlag
⇒ Medenbach, O .; Sussieck-Fornefeld, C .; Steinbach, G. (1996): Steinbach's natural guide minerals. 223 species descriptions, 362 color photos, 250 drawings and 30 pages of identification tables. Mosaik Verlag Munich
⇒ Schumann, W. (2017): Precious stones and gemstones. All kinds and varieties. 1900 unique pieces. BLV determination book, BLV Verlagsgesellschaft mbH Munich
⇒ Hochleitner, R. (2017): Which stone is that? Kosmos nature guide. Over 350 minerals, gemstones and rocks. Franckh Kosmos Publishing House
⇒ Schumann, W. (1992): Precious and precious stones: all precious and precious stones in the world; 1500 unique pieces. BLV determination book, BLV Verlagsgesellschaft mbH Munich
⇒ Schumann, W. (1991): Minerals rocks - characteristics, occurrence and use. FSVO nature guide. BLV Verlagsgesellschaft mbH Munich
- www.mindat.org - rutile

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