Adularescence is a vibrant, natural optical effect similar to the shimmering appearance of the moon on a cloudless evening. Its name is derived from “adularia”, a mineralogist term for Moonstone.
When a gem displays an attractive light, which appears to float below its surface, the effect is known as adularescence. Caused by the physical crystal structure in certain gemstones, it can be seen near the surface of several gems where a ghost-like reflection with a bluish-whitish colour is visible. To maximise this glorious visual effect, these gems are often cabochon cut.
This shimmering effect is visible only in certain gemstones that have a layered type structure. These layers alternate in thickness; the thinner ones are so small that the eye cannot detect the visible wavelengths, scattering the light in multiple directions.
When adularescence is witnessed in Labradorite it is often referred to as labradorescence. In Opals it is known as opalescence, but be careful not to confuse this with ‘play of colour’, which is a different optical phenomena. Although the effect is most noticeable in Moonstones, Labradorite and Opals, you can occasionally see it in Rose Quartz and some Brazilian Agates.
In Southern Brazil we unearthed some very unusual Lavender Quartz and every single piece demonstrated wonderful adularescence.
