View example sentences and word forms for Perthite.
Perthite
Perthite meaning
A laminated mixture of two feldspars: plagioclase and either orthoclase or microcline.
Example sentences (4)
Feldspar (Amazonite) Perthite is either microcline or orthoclase with thin lamellae of exsolved albite.
If the high temperature intermediate composition alkali feldspars are allowed to cool slowly, exsolution occurs and a perthite structure results.
In the acid rocks the common feldspars are orthoclase, perthite, microcline, and oligoclase—all having much silica and alkalis.
Perthite is a typical texture in alkali feldspar, due to exsolution of contrasting alkali feldspar compositions during cooling of an intermediate composition.