Moonstone: meaning, properties and lore

The mineral

Moonstone is a variety of the feldspar-group mineral orthoclase, and it is perhaps the most familiar gem-quality member of the feldspar group. Feldspars are the most widespread minerals in the earth's crust, and they make up more than half of the Earth's rocky crust.¹²³⁴

Moonstone is composed of two feldspar minerals, orthoclase and albite, which are intermingled at first. As it forms, the two separate into alternating layers, and these layers give the stone its sheen. Its internal structure scatters light, producing adularescence, a light that appears to move across the gem.^12349106

Moonstone's hardness on the Mohs scale is 6.0 to 6.5, and its specific gravity is 2.58. Its refractive index is 1.518 to 1.526. The stone has poor toughness and two cleavage directions, a trait it shares with other feldspars. Cleavage is a direction of atomic weakness that makes moonstone more prone to breaking.¹³⁴⁵⁶

Moonstone occurs in colorless, white, gray, green, peach and brown colours, and its bodycolors range from green and yellow to brown and gray to nearly black. Moonstones range from semitransparent to opaque, with a blue, silver, or white adularescent effect. Some stones show chatoyancy, also called the cat's-eye effect, and a few show four-rayed stars called asterism. Moonstone displays light yellow pleochroism.¹⁹³¹¹⁴

Characteristic inclusions in moonstone include tiny tension cracks called centipedes. Inclusions can potentially interfere with adularescence, so a good moonstone should be almost transparent and lacking inclusions as far as possible. The Ceylon material occurs as phenocrysts in liparitic rock, from which the crystals are easily separated.^1113947

Mt. Adular (now St. Gotthard) in Switzerland was one of the first sources of fine-quality moonstone. Moonstone from Korea also shows schillarization. A new type of rainbow moonstone with orange flash effect has been reported from Madagascar, and in 1997 miners in Southern India discovered a bright green type called parrot green. Labradorite found mainly in Labrador, Canada, can show adularescence, and labradorite from Madagascar is sold as rainbow moonstone, which is not orthoclase.^10711124

History and lore

Wilkie Collins's novel The Moonstone recorded that a semi-transparent stone of the inferior order of gems was once supposed in ancient Greece and Rome to be affected by lunar influences, and that collectors still knew it by the moon's name. The narrator of the romance wrote that the Indian Moonstone was said to be set in the forehead of the four-handed Indian god who typifies the Moon, according to the earliest traditions.¹²¹³

The stone gained the name Moonstone from its peculiar colour and from a superstition that it grew and lessened in lustre with the waxing and waning of the moon. The name moonstone comes from its moon-like features, and many cultures link the gem with moonlight. Adularescent moonstone was once called adularia, a name that originated with Mt. Adular in Switzerland.¹³⁹¹⁰

In Hindu legend, moonstone is made of solid moonbeams. Other legends say that moonstone brings good luck, and legends say that moonstone brings good luck in the same way as other lunar tales.⁹⁴¹⁰¹⁴

Kozu and Endo note that the moonstone from Ceylon had been regarded by mineralogists as a variety of adularia with schillarization, but they argue important physical and chemical differences exist. Mr. S. Kozu's investigation of adularia and moonstone was commenced at Cambridge and published in Science Reports of the Tohoku Imperial University in 1921. Warren's work on perthitic feldspars, with a published date of 1915, gave limits on how much albite can be held in potassic feldspar.⁷⁸

Moonstone was a favorite among Arts and Crafts artisans in the last half of the nineteenth century, who used it in handcrafted silver items. René Lalique and Louis Comfort Tiffany, great designers of the Art Nouveau era, featured the pale gem in custom jewelry. Moonstone has fascinated designers and gem connoisseurs for centuries.¹⁰¹¹

During the 1960s flower child movement, moonstone provided its wearers with the desired ethereal look. Designers of the 1990s New Age movement turned to moonstone's natural beauty for inspiration. Moonstone is popular for carving into cameos and man-in-the-moon faces, which combine with the shifting adularescent sheen.¹⁰¹¹

Birthstone and other links

Moonstone is a June birthstone, listed along with pearl and alexandrite.^1310615

Some consider moonstone an alternative birthstone for those born on Monday, the Moon's day, according to crystal practitioners. Moonstone was named the state gem of Florida, a link given by crystal practitioners. Practitioners tie these lunar links to the Moon's influence, and the Monday link is a modern one.¹⁶¹⁵

What crystal practitioners say

Crystal practitioners associate moonstone with the mind and emotions. Crystal healers say moonstone helps bring out an empathic response and feeling back to those who have been numb. Believers hold that moonstone has a calming influence and can help people enter a trance. Some regard moonstone as an excellent aid for those with trouble sleeping, given its lunar association and purported calming influence.¹⁶¹⁵

Practitioners associate moonstone with sleep and dreams. Moonstone is said to assist with lucid dreaming when tucked beneath one's pillow. Current folklore holds that moonstone helps wearers go with the flow, similar to the moon affecting the tides.¹⁶¹⁴

Mystics around the world have used moonstone for meditation, with its moving inner light serving as a focus. Practitioners describe the stone's finest quality as a gem with a mobile, electric blue shimmer, which they regard as the sheen to favour. Crystal practitioners associate the sheen with the Moon's changing light during meditation.¹⁵¹¹¹

Magicians used moonstone for spells of increase as the Moon waxed and for spells of decrease as the Moon waned. Some regarded moonstone as an excellent protective talisman to wear on sea voyages or while swimming, since the Moon influences the waters. Some supposed moonstone could help wearers regain or retain a more youthful appearance and bearing, since the Moon renews itself monthly.¹⁵

Those seeking their true love were told to hold the stone during a full moon, envisioning their love, then carry it until the next full moon. Lovers often exchanged moonstones, especially after quarreling, to help restore love and tranquility.¹⁵⁶¹⁴

Practitioners use moonstone as a home and personal stone for cleansing and care. Manufacturers usually set moonstone into pendants, earrings, and pins rather than rings because cleavage can affect durability.⁵

Crystal healers and believers make claims for the body and the female cycle. According to them, moonstone helps bring menstruation into line with the lunar cycle, with ovulation at full Moon and menstruation at new Moon. Believers also say the stone helps a woman accept her femininity and live with it with enjoyment. Further, it is said to delay and harmonise the drop in oestrogen during menopause, so the change takes place with fewer problems.¹⁷

Some Middle Eastern women sew moonstones into their clothing to help them have a child, a practice described as still around today. High heat or sudden temperature change can cause breaks in moonstone, so practitioners who wear it are advised to keep it away from heat.¹⁶⁵

What testing has found

In his analysis of 150 complementary and alternative treatments, Edzard Ernst found no rigorous trials that test the therapeutic value of crystal healing. He concluded that no scientific proof exists for any positive effect beyond placebo. Crystal healing is regarded as harmless and without toxicity.¹⁸

A 2001 study by British psychologist Christopher French challenged 80 volunteers to tell real crystals from fake ones after holding them and meditating. Participants felt effects such as warmth, tingling, or well-being that they had been primed to expect, and six people felt nothing at all. Participants could not tell the real quartz crystals from the fake glass ones, and both groups reported similar impressions, suggesting a placebo effect.¹⁸¹⁹

The scientists concluded that the power of suggestion, not the crystals, produced the effects. Ted Kaptchuk, a Harvard Medical School professor, argues that placebo effects from unconventional medicine should not be discarded.²⁰

Some researchers say crystals likely do not directly act on physical and psychological problems, but may have indirect benefits explained by the placebo effect. Rigorous scientific research into crystal therapy is lacking, and few studies have compared it with other therapies. Jarry says that alternative medicine's reputation benefits strongly from non-specific placebo effects and regression to the mean.²⁰¹⁸