Andesine is a silicate mineral , a member of the plagioclase series. Its chemical formula is (Ca , Si ) is between 30–50%. The formula may be written as Na0.7-0.5Ca0.3-0.5Al1.3-1.5Si2.7-2.5O8.
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
It is sometimes used as a gemstone