Aventurine and moonstone varieties occur, though these special appearances are more usually displayed by the oligoclase and orthoclase felspars respectively.
They rarely display lamellar twinning and give extinctions measured from the long axis of oligoclase and oligoclase andesine (2°-8°).
The variety of plagioclase ranges between oligoclase and andesine labradorite.
Under the microscope it is displayed as a colourless glass inclosing phenocrysts of sanidine, oligoclase (ext.
Their extinctions are those of oligoclase and acid andesine.
This rock displays a few small phenocrysts of oligoclase and pyroxenes in a blurred glassy groundmass exhibiting the felspar and pyroxene microliths in process of development (sp.
A rock frequently exposed between Tawaki and Mount Thuku[125] contains abundant phenocrysts of glassy felspar (oligoclase and sanidine) and quartz in a greenish opaque groundmass having a blurred microfelsitic structure.
Portions of crystals of glassy felspar (oligoclase and sanidine) also occur in it, together with some quartz and rhombic pyroxene.
Lamellar twinning is rare, the extinctions being those ofoligoclase andesine (10° to 20°).
Under the microscope the felspar is mainly orthoclase with perthite or microcline, while a small amount of plagioclase (ranging from oligoclaseto albite) is practically never absent.
The felspar of the granulites is mostly orthoclase or cryptoperthite; microcline, oligoclase and albite are also common.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "oligoclase" in a variety of sentences. We hope that you will now be able to make sentences using this word.
