Sunstone, 54 pieces, beautifully individually packaged in a counter display box. For years, a big sales hit.

The mineral oligoclase or sunstone is a sodium-calcium-aluminum tectosilicate with the chemical formula (Na,Ca)(Si,Al)4O8. It belongs to the feldspars. The colorless, greenish, gray, or brown oligoclase has a glassy luster, a white streak color, perfect cleavage according to crystal face [001], and good cleavage according to [010]. The average density is 2.65 and the hardness is 7. The crystal system is triclinic and the mineral is neither radioactive nor magnetic. The name of the mineral oligoclase is derived from the Greek words oligos and klasein, "to split little." Oligoclase is a common feldspar in metamorphic and igneous rocks such as pegmatite. It is part of the plagioclase series (albite-anorthite). The type locality of oligoclase is Twedestrand in Norway. Presumably, the Vikings used oligoclase as a navigation instrument to determine the position of the sun at sea during cloudy weather. This mineral can make polarized light visible that forms rings around the sun due to refraction in the atmosphere. The crystal doubles the rings. If both are equally visible, the crystal is directly aligned with the sun. The rings are also visible when the sun is already a bit below the horizon.