The Oregon Sunstone was designated Oregon’s Official State Gem by the Oregon legislature in 1987.
What is the sunstone made of?
Sunstone is a member of the feldspar family. Feldspars are the most abundant minerals in the earth's crust. They are, for example, part of the composition of granite, quarts and mica, but they are also found as gemstones.
Within the wilderness, the majority of feldspars are separated into two distinct categories:
- Calc-sodium feldspars or plagioclases (very low in potassium)
- The alkaline feldspars (very poor in calcium)
Among the calcosodic feldspars or plagioclases, we find minerals very important in gemology as andesine, labradorite and oligoclase that can often be found in commerce as moonstone or sunstone. (Thoreux E., 2019, p.4).
Oregon sunstone is a natural cupriferous feldspar of the labradorite type. Its colours vary depending on the presence of copper in its crystal structure (Pay & Al., 2013). The more copper within the stone, the darker the complexion. Although a large amount of sunstones are pale yellow-pink, some of them show a dichroism from red to green.