File talk:Feldspar group.svg

Plagioclase formula

The Plagioclase feldspars formula Na_xCa_(1-x)Al_(2-x)Si_(2+x)O₈ does not correspond directly to the text Oligoclase 10-30% An and so on. I suggest Na_(1-x)Ca_xAl_(1+x)Si_(3-x)O₈. Any other opinion? --Stenallan (talk) 09:45, 28 November 2019 (UTC)