What are the characteristics of moonstone crystal from different origins? What is the moonlight effect? How does it arise?

Moonstone crystal is primarily found in Sri Lanka, Burma (Myanmar), India, Brazil, Mexico, and the Alps in Europe, with production also occurring in Inner Mongolia, China. Among these, the ones from Sri Lanka are considered the most precious.

Characteristics of Sri Lankan Moonstone Crystal

It exhibits only blue sheen, and the crystal has a hazy, creamy appearance that is very smooth and comfortable to look at. Larger, flawless specimens are relatively common, with a few being transparent and colorless like glass, though their transparency slightly differs from those found in India.

Advantages of Sri Lankan Moonstone

Good luster, predominantly flawless, but exclusively with a blue sheen, primarily creamy in appearance, with a few exceptions of glass-like transparency.

Characteristics of Indian Moonstone Crystal

Features both rainbow and blue sheens, and the crystals are mostly clear glass bodies. Smaller crystals free of frost or cotton-like inclusions are especially prized, as they are often cut from larger stones.

Processing Techniques

Most crystals are characterized by more frost or cotton-like inclusions because these are not typically avoided when cutting and polishing the gem, which allows for larger pieces to be shaped into spheres and other forms. Larger stones are also utilized for carvings, and many are set into 925 sterling silver jewelry.

Advantages of Indian Moonstone

Good luster is noted, although the crystals often have cotton-like inclusions. Nonetheless, a few of good quality are certainly available.

Characteristics of Burmese Moonstone Crystal

The glass-like bodies of the Burmese moonstone crystal are generally of good quality but possess a weaker blue sheen. By Burmese craftsmen, these stones are often set in simple copper mountings for sale, mirroring their tradition of selling jade cabochons.

Under fluorescent light, the photographs of the crystals might appear bluer, but this tends more towards the crystal’s inherent blue rather than a scattered blue light. When reset and photographed under natural light, the weaker blue sheen is clearly visible; however, it does not stand out when worn daily.

Advantages of Burmese Moonstone

Glass-like bodies are mostly flawless, but with a definitively weak blue sheen (large surface area, weak intensity), although a few exceptions may exhibit stronger luminescence.

Understanding the Moonlight Effect

What is the moonlight effect? It is a luminescent effect that can be observed from certain angles as the gemstone is rotated, typically appearing white to blue, resembling hazy moonlight.

Causes of the Moonlight Effect

The luminescent effect of moonstone crystal, also known as adularescence, is believed to be caused by the scattering of light. This adularescence, also referred to as schiller or sheen in orthoclase, is produced by the interference of light which is diffusely reflected from microscopic twin lamellae of albite within the orthoclase.

Distinctiveness of Moonstone Crystal

Moonstone crystal, akin to the luminous moon with its mesmerizing adularescence, resembles the hazy moonlight. Although many gemstones in nature exhibit this moonlight effect, it is only when it occurs in feldspar minerals that the stone can be rightly called moonstone crystal, marking its unique distinction.