22
Jun
Types Of Twinning In Minerals. Two common kinds of twinningthose designated Carlsbad twinning and albite twinningare shown in the figure. Twinning or twinning tendencies may either promote or preclude the use of mineral in industry like twinning in quartz preclude the use of quartz either lens or oscillator. Named after the mineral Spinel which often exhibits this form of twinning. Twinning is a distuinguishing feature in thin section of many minerals like in plagioclase polysynthetic twinning microclinecross hatched twinning orthoclase simple twinning or in many other minerals.
Carlsbad twinning occurs in both monoclinic and triclinic feldspars. The minerals rutile TiO2 and cassiterite SnO2 commonly show this type of twinning. Make a sketch of a mineral showing each of the following. There are two types of repeat twinning. Adularescence is also known as Schiller. WHY WE STUDY TWINNING.
Hexagonal System -The minerals calcite CaCO3 and quartz SiO2 are the most common hexagonal minerals and both show the types of twinning common in hexagonal minerals.
In this plane parallel to b-pinacoid is the twinning plane. Make a sketch of a mineral showing each of the following. The minerals rutile TiO 2 and cassiterite SnO 2 commonly show this type of twinning. In this plane parallel to b-pinacoid is the twinning plane. There are two types of repeat twinning. An axis about which a 180 degree rotation of one half of twinned crystal would convert into a single crystal.