Specimens Oligoclase is not a well known mineral but has been used as semi-precious stone under the names of sunstone and moonstone. Sunstone has flashes of reddish color caused by inclusions of hematite.
Moonstone shows a glowing shimmer similar to labradorescence, but lacking in color.
The display is produced from lamellar intergrowths inside the crystal. These intergrowths result from compatible chemistries at high temperatures becoming incompatible at lower temperatures and thus a seperating and layering of these two phases. The resulting shimmer effect is caused by a ray of light entering a layer and being refracted back and forth by deeper layers before it exits the crystal. This refracted ray has a different character than when it went in and produces the moonlike glow. Oligoclase is a member of the Plagioclase Feldspar Group.