Adularescence effect in Gemstones
by NASRINA PARVIN KHAN
The milky, bluish/white sheen named as adularescence in moonstone appears to float along the transparent body. Thus the phenomenon adularescence seems to be move around the body of the stone when it is turned.
Special optical phenomenon is the property of gems which give the distinct identity of gems and add value. Adularescence is such a phenomenon that has been specially seen in moonstone.
A milky sheen or wavy glowing light effect which appears to come from below the surface of the gems is known as adularescence. Orthoclase feldspar named moonstones is the only example which exhibits the true adularescence.
Sometimes, a golden shifting light displayed by certain quartzes and opals in the interior of them is known as “adularescence”. But usually it is called as “girasol” effect.
Adularescence in moonstones
Adularescence of moonstone and Labradorscene of Labradorite are related phenomena and looking similar. Both the gems belong to feldspar family and this is the reason of their similarity.
The milky, bluish/white sheen named as adularescence in moonstone appears to float along the transparent body. Thus the phenomenon adularescence seems to be move around the body of the stone when it is turned.
The name adularescence derives from “adularia”. Because the moonstone which posses the phenomenon mainly historically known as “adularia”.
image: Mineralminers.com
The most popular color of moonstone is blue, but it also found in gray, white, pink, green and brown etc. normally the nature of moonstone is transparent to translucent.
Traditionally moonstone came from the country Sri Lanka. The Sri Lankan moonstone are classical bluish and nearly transparent in nature. They are also found in USA, Australia, Brazil, Myanmar, Madagascar and India. Indian specimen shoe cloudy plays of light with beige brown, brown, orange, green background.
The distinct pearly moon like glowing shimmer of moonstone caused by the reflection of light.
How Adularescence happens?
The structural pattern of the gem is the reason of this distinct optical phenomenon. Moonstone is made up of potassium Aluminium silicate. Adularescence is caused by the layer effect due to presence of tiny inclusions of another feldspar in the host material. Inclusions of sodium feldspar by exclusion in the potassium feldspar create a layer, where thin inner strata of two types of feldspar intermix. Interference effect of light occurs in gems due to these layers. Reflected light scatters equally in all spectral regions and produce a shiller. The colors of the shiller may be white, blue or blue-and orange by this phenomenon. But the valuable as well as desirable color of this shiller is blue, which is usually produced by a white or gray body colored stone. Thin layers help to produce attractive shiller, whereas less attractive whitish shiller produced by thick layers. The size or distance from layer to layer determines the colors we see in many cases.
Unique play of light, which called as adularescence, makes moonstone very special. Cutting is very important for moonstone to show the phenomenon adularescence. The stone must be cut as tall, domed shape, which called as cabochon to exhibit the phenomenon. The exact height of the stone is very essential. Thereafter the axis of the crystal must be located exactly in the zenith of the stone.
Polishing is also important to get the desired effect. A dulled moonstone can be obtained the magical effect of adularescence by the polished in such a way.
Usually, the moonstone are available in transparent to translucent way. But a larger and more transparent stone is more valuable than others. Intensity of the color is also add value to the stone.
The soft, sensuous, mysterious glowing light effect named as adularescence in moonstone gives the stone a feminine character and makes it attractive. Moreover the movement of the stone helps to exhibit the phenomenon adularescence. So, to create the seductive charm of adularescence in moonstone, it requires be wearing and moving a lot.
Actually the astonishing effect of adularescence makes the moonstone seductive, sensuous and highly desired and more valuable.
