Feldspar is one of four groups of minerals belonging to the tectosilicate family, which in turn is subdivided into three types and two classes/series. Heliolite or Sunstone belongs to the same plagioclase series as Labradorite. It is also called Aventurine feldspar as it has a similar metallic sheen as Aventurine quartz, but with Sunstone it is due to the presence of red copper. Sometimes it also contains flecks of hematite. The more copper it contains, the deeper the orange color.
Moonstone on the other hand is composed of two types of feldspar and presents the same opalescent Schiller effect or light diffraction as labradorite. It exists in countless colors ranging from colorless to deep grey and in blue, green, peach, pink and brown. The Greeks and Romans associated this stone with the lunar deities. It was one of the favorite gemstone of the French goldsmith René Lalique (Art Nouveau).