Sunstone from the Bjordam Quarry, Norway

This sunstone specimen comes from the Bjordam Sunstone Quarry near Bjordammen in Bamble, Telemark, Norway. One side has been polished to make the reflective inclusions within the feldspar more clearly visible.

Under direct illumination, the polished surface displays orange-red to copper-colored aventurescence. This glittering effect is caused by fine, preferentially oriented hematite inclusions within the feldspar. The intensity of the reflections changes depending on the angle of illumination.

With dimensions of 3.4 × 3.0 × 1.0 cm, the piece belongs to the miniature specimen size category.

Aventurescent Oligoclase from Bjordammen

The Bjordam Sunstone Quarry is a specialized Norwegian locality for aventurescent plagioclase feldspar. Material from this locality is predominantly described as oligoclase sunstone.

Oligoclase belongs to the plagioclase series and is a sodium-rich feldspar. The characteristic aventurescence of the material from Bjordammen is caused by fine hematite platelets that reflect incoming light.

The polished display surface clearly reveals the orange-red to copper-colored reflections. The unpolished edges also preserve the natural appearance of the specimen.