Teschenite is a type of coarse or medium grainedigneous rock, akin togabbro ordolerite, that contains essentialanalcime. Its name is derived from the region ofTeschen, where it was discovered. The termcrinanite has previously been used as a synonym for teschenite (particularly for deposits with increased analcime content),[1] but there have been attempts to standardise terminology by stopping its use.[2][3] Rocks related to teschenite are referred to as rocks of theteschenite association.[4]
Teschenite is typically composed of essentialtitan-augite,analcime,labradorite and small quantities ofolivine and may includehornblendes; the presence of analcime is a key characteristic of teschenites and its presence is a factor that differentiates it from other similar rocks.[5][6]
Teschenite also has subtypes such ascuyamite andlugarite.[7]
Teschenite was first described and named byLudwig Hohenegger [cs] in 1861.[5][8][9] Hohenegger used the term to describeCretaceous masses ofAustrian Silesia nearTeschen, which up until that point were listed as a range of minerals, such asdiorite,diabase,greenstone orflood basalt, among others. Later in 1866 Hohenegger's definition of the mineral was further refined byGustav Tschermak, who differentiated between the darker, basalt-like deposits rich inolivine and what is now called teschenite as he identified the former aspicrite.[5]
Until 1892 the name in use for the rock wastchesenit, which is derived from the German name for Český Těšín. The name teschenite (těšínit in Czech) was first used by mineralogistJosef Klvaňa [cs][10]
Teschenite has been found in many parts of the world, some examples include Scotland, Portugal, theCaucasus Mountains,Siberia, Kenya, Myanmar, Taiwan, Australia and New Zealand.[6][11]
In the Czech Republic, teschenite is primarily found in the volcanic region of theBeskids which stretch from the borders ofMoravia to regions east ofČeský Těšín.[12] Specific documented deposits are inTichá, in the basin of theOstravice river, in theŘepiště municipality and in a quarry nearŽermanice Reservoir.[12][6][13][14][15] Historically, olivine-rich teschenite has also been mined in an old quarry inStraník.[16]