A sample of Oregon sunstone from the GIA Museum’s collection was found to contain some unusual inclusions that appeared yellow in transmitted light and iridescent in reflected light. Vivid shades of yellow, blue, and purple were visible in a concentric pattern when illuminated with a fiber-optic light (figure 1). Some of the inclusions contained a metallic copper center and appeared darker than the surrounding inclusion under brightfield illumination (figure 2). The series of parallel lines pictured are also thought to be copper inclusions.
These inclusions looked pyritic in nature and possibly altered as a result of heating. This may well be natural heating from processes within the earth, as Oregon sunstone is not known to be treated.
A sample of Oregon sunstone from the GIA Museum’s collection was found to contain some unusual inclusions that appeared yellow in transmitted light and iridescent in reflected light. Vivid shades of yellow, blue, and purple were visible in a concentric pattern when illuminated with a fiber-optic light (figure 1). Some of the inclusions contained a metallic copper center and appeared darker than the surrounding inclusion under brightfield illumination (figure 2). The series of parallel lines pictured are also thought to be copper inclusions.
These inclusions looked pyritic in nature and possibly altered as a result of heating. This may well be natural heating from processes within the earth, as Oregon sunstone is not known to be treated.
