Moonstone

What is Moonstone?

Moonstone is a gemstone variety of the Feldspar mineral group — specifically the orthoclase and albite feldspar minerals, which together account for more than half of the earth's crust. What makes Moonstone exceptional within this vast mineral family is its extraordinary internal structure — alternating microscopic layers of two distinct feldspar types (orthoclase and albite) that interact with light to produce the breathtaking optical phenomenon known as adularescence. Moonstone ranks 6 to 6.5 on the Mohs scale of hardness — making it suitable for pendants, earrings, and bracelets, and for rings with appropriate protective settings.

The name 'Moonstone' derives from the stone's most defining characteristic — its remarkable resemblance to the soft, glowing light of a full moon. The word 'adularescence' itself comes from 'adularia' — an old name for Moonstone that references an ancient source of high-quality specimens from the city of St. Adular in Switzerland. Today, the finest Moonstone in the world comes from the gem gravels of Ceylon (Sri Lanka) — producing the extraordinarily rare transparent blue sheen variety that is among the most beautiful and collectible gemstones available.

Adularescence — The Magical Glow That Defines Moonstone

Adularescence is the single most defining and most magical characteristic of Moonstone — the optical phenomenon that gives this gemstone its extraordinary, otherworldly beauty. It is important to understand that adularescence is not a surface sheen, a coating, or a polish effect — it is an entirely natural optical phenomenon that originates deep within the internal structure of the stone itself.

How Adularescence is Created — The Science Behind the Magic

During the formation of Moonstone deep within the earth, two types of feldspar — orthoclase and albite — cool and solidify together, but separate into alternating microscopic layers as they cool at different rates. These layers are incredibly thin — ranging from just a few nanometres to several hundred nanometres in thickness — and are stacked in alternating bands throughout the entire crystal.

When light enters the Moonstone and strikes these alternating layers, it is scattered and diffracted — bouncing between the layers and emerging from the stone as a soft, billowing, cloud-like glow that appears to float and move beneath the surface of the stone as it is tilted and rotated. This is adularescence — a three-dimensional internal light that seems alive, as though the moonlight itself is captured within the stone.

The colour of adularescence depends on the thickness of the albite layers: very thin, fine albite plates produce the most coveted vivid blue adularescence — the hallmark of the finest Ceylon Moonstone. Thicker albite plates scatter light differently, producing a white or silver adularescence — seen in most multicolour and translucent varieties. The finest blue adularescence appears to have a remarkable three-dimensional depth — as though the blue glow is suspended within a pool of light inside the stone.

How to Observe Adularescence

To fully appreciate a Moonstone's adularescence — hold the stone approximately 30 cm from a single light source and slowly tilt and rotate it. The adularescent glow should appear to float smoothly across the top of the cabochon, moving with the stone as it tilts. In the finest Ceylon Blue Sheen Moonstone, the blue glow should be vivid and centred — visible from a wide range of angles, not just from one specific direction. A sheen that is only visible from a very narrow angle is considered of lower quality.

The Centipede Inclusion — Moonstone's Unique Natural Signature

One of the most fascinating and uniquely characteristic aspects of genuine natural Moonstone is its distinctive natural inclusion known as the 'Centipede' inclusion — a feature so specific to Moonstone that its presence under magnification is one of the most reliable methods gemologists use to confirm a stone's identity as genuine natural Moonstone.

Centipede inclusions are tiny stress fractures and tension cracks that form within the Moonstone crystal during its natural growth and cooling process — caused by the internal pressures created as the alternating feldspar layers contract and expand at slightly different rates. When viewed under magnification, these inclusions appear as fine, sinuous fractures with small offshoots branching from a central line — creating a pattern that unmistakably resembles the long, thin body and multiple legs of a centipede, hence the name.

What makes centipede inclusions particularly fascinating is their intimate relationship with the very structure that creates adularescence. Because centipede inclusions form along the boundaries between the alternating feldspar layers — the same layers responsible for the adularescent effect — they are in fact a natural consequence of the internal structure that makes Moonstone magical. In this sense, centipede inclusions are not simply flaws — they are a direct expression of Moonstone's most defining characteristic.

Moonstone Gemstone Properties

Moonstone Varieties — A Complete Guide

Moonstone occurs in a beautiful range of varieties — each distinguished by its body colour, transparency, and the character of its adularescence. Here is a comprehensive guide to all the varieties Shubh Gems offers:

Ceylon Blue Sheen Moonstone — The Rarest & Most Precious

The Ceylon Blue Sheen Moonstone is the most extraordinary, most rare, and most valuable variety of Moonstone in the world — a gemstone of genuinely exceptional rarity and beauty. It is characterised by a fully transparent to near-transparent, colourless or pure white body — with absolutely no significant secondary colour — displaying a vivid, electric blue adularescence that floats with breathtaking three-dimensional depth within the stone.

What makes this variety so uniquely precious is the extraordinary combination of its qualities — a perfectly transparent body that allows light to pass through completely unobstructed, combined with the most vivid blue adularescence that nature can create within Moonstone. The transparency of the body is essential — it is what allows the blue sheen to glow with its full, unimpeded three-dimensional brilliance. Any cloudiness or opacity in the body significantly reduces the depth and vividness of the blue glow.

Ceylon Blue Sheen Moonstones of fine quality seldom exceed 15 to 20 carats — and stones above 5 carats with strong, vivid blue adularescence and excellent transparency are genuinely exceptional and extremely rare. This combination of rarity and extraordinary beauty makes fine Ceylon Blue Sheen Moonstone one of the most sought-after gemstones among serious collectors and connoisseurs worldwide.

Multicolour Translucent Moonstone — Peach, Gray & Soft Delicate Tones

The Multicolour Translucent Moonstone encompasses a beautiful and diverse range of Moonstone varieties — characterised by a translucent (rather than transparent) body in a spectrum of soft, delicate, and warm colour tones — most commonly peach, gray, and white, with occasional stones in soft apricot, cream, or light lavender tones. These varieties display a white to silver adularescence — a gentle, milky glow that adds warmth and softness to the stone's already beautiful body colour.

Peach Moonstone — the most popular of the multicolour varieties — displays a warm, glowing apricot-peach body colour with a soft white adularescent sheen. Its warm, feminine energy and beautiful colour make it one of the most beloved Moonstone varieties for jewellery.

Gray Moonstone — sometimes called 'New Moon Stone' — displays a cool, sophisticated gray body colour with a pearly white sheen. Its subtle, contemporary aesthetic makes it a popular choice for modern jewellery design.

White Translucent Moonstone — a milky, translucent white variety with a soft white or silver sheen — is the most widely available and most widely used Moonstone variety. While less rare than the Ceylon Blue Sheen, a fine quality white translucent Moonstone with a strong, centred silver sheen is a beautiful and meaningful gemstone.

Cat's Eye Moonstone — Chatoyancy on Moonstone

Cat's Eye Moonstone is a special variety that displays chatoyancy — the 'cat's eye' effect — in addition to adularescence. This optical phenomenon is caused by parallel needle-like inclusions within the crystal that reflect light as a single, sharp band across the surface of the cabochon — resembling the slit pupil of a cat's eye. When adularescence and chatoyancy occur together in a Moonstone, the result is a uniquely beautiful and rare stone that displays both a floating glow and a sharp eye simultaneously.

Star Moonstone — Asterism on Moonstone

Star Moonstone is one of the rarest Moonstone varieties — displaying asterism — a four-rayed star effect — in addition to adularescence. This phenomenon occurs when needle-like inclusions align in multiple directions within the crystal, creating a star pattern that appears to float above the adularescent glow. Fine Star Moonstones — particularly those from Ceylon showing both a strong star and vivid adularescence — are among the rarest and most collectible Moonstone specimens.

Moonstone Varieties — Quick Reference

Moonstone Sources & Origins

Ceylon (Sri Lanka) — Source of the World's Finest Moonstone

Ceylon (Sri Lanka) is the world's most celebrated and prestigious Moonstone source — and the exclusive origin of the finest transparent blue sheen Moonstone. The ancient alluvial gem gravels of Sri Lanka — particularly around the Meetiyagoda region — have produced some of the most extraordinary Moonstone specimens ever found. Ceylon Moonstone is celebrated for its exceptional transparency, vivid three-dimensional blue adularescence, and superior clarity — qualities that simply cannot be replicated by Moonstone from any other origin.

Fine Ceylon Blue Sheen Moonstone is becoming increasingly scarce — as decades of mining have gradually depleted the most accessible deposits of this extraordinary material. This growing rarity — combined with the stone's extraordinary beauty — is driving prices steadily upward, making fine Ceylon Moonstone an increasingly sought-after collector's and investor's gemstone. Shubh Gems sources Ceylon Moonstone exclusively from certified dealers in Sri Lanka — ensuring every stone is genuinely natural and of confirmed Ceylon origin.

India — Rich Source of Multicolour & Peach Moonstone

India — particularly the states of Rajasthan and Bihar — is one of the world's most significant Moonstone sources, producing the majority of the world's commercial and fine quality multicolour, peach, gray, and white translucent Moonstone. Indian Moonstone is known for its warm, rich body colours and good quality adularescence — offering beautiful, accessible Moonstone in a wide variety of colours and qualities. Indian Moonstone does not typically produce the transparent blue sheen variety — but its warm peach and gray varieties have their own distinctive and widely loved beauty.