Sometimes also known as aventurine feldspar, it owes its attractiveness to the inclusions of red, orange and occasionally green thin platy crystals of goethite or hematite which are disseminated in parallel orientation through the near colorless matrix. The inclusions give the mineral a rich reddish-brown color with spectacular colorful reflections.
Plagioclase (Na-Ca feldspar: albite, oligoclase, andesine,
labradorite,bytownite, anorthite) are part of an isomorphous series, and our sunstone is somewhere in the oligoclase area, i.e. with more Na than Ca).
