Andesine is a silicate mineral, a member of the plagioclase feldspar solid solution series.

[2] The plagioclase feldspars are a continuous solid solution series and as such the accurate identification of individual members requires detailed optical study, chemical analysis or density measurements.

Refractive indices and specific gravity increase directly with calcium content.

[7] Andesine occurs in intermediate igneous rocks such as diorite, syenite, and andesite.

It characteristically occurs in metamorphic rocks of granulite to amphibolite facies commonly exhibiting antiperthite texture.