While the potassium and you may sodium try chemically equivalent — he or she is alkali material factors — and you can have a tendency to function singly charged ions, K + & Na + , when you’re calcium was chemically a little various other (an enthusiastic alkaline world ) and you may versions doubly energized ions, Ca +dos (which means we need a couple aluminum atoms for two silicons, instead of one for three that have potassium and you will sodium), we might predict potassium and you can salt feldspars as chemically more off calcium feldspar. However, that is simply part of the tale.
It turns out, basalts and you can gabbros choose calcium supplements and granites and you will rhyolites prefer the akalis
Potassium feldspar, KAlSi3O8 is relatively distinct as Orthoclase (”straight break” in Greek), while sodium, NaAlSi3O8 and calcium, CaAl2Si2O8 , feldspars form the Plagioclase Series (”slanting break” — both names describe characteristics of the crystals).