Sunstone (Aventurine feldspar)

Sunstone owes its name to a sparkling optical effect called aventurescence, produced by reflections from aligned platelet inclusions of copper, hematite, or goethite suspended within the stone. It is a variety of feldspar, typically oligoclase or labradorite. Oregon sunstone, the official state gemstone of Oregon, contains native copper inclusions that yield colors ranging from pale yellow to deep red, while Scandinavian material shows a warm golden schiller. Its metallic, spangled brilliance and warm tones have made it a popular gem. With a Mohs hardness of 6 to 6.5, sunstone is moderately durable and is cut both as faceted stones and as cabochons that best display its shimmer.