“I loved to think that Moonstones were made by the breaking-off of minute portions from the moon itself, which after travelling about a while in space finally reached earth.”
Louis Kornitzer, Gem Trader (1939)
Moonstone: the raw crystal and processed gem
Also known as Selenite and Adularia, Moonstone owes its name to its similarity with the moon. The term Selenite derives from the Greek ‘selene,' meaning moon and the name for the moon goddess in Greek mythology. Adularia is the name for a variety of Moonstone found in the European Alps, which draws its name from the optical phenomenon that characterizes Moonstone, called adularescence. The Hindi name for Moonstone is ‘chandrakant,' meaning ‘beloved of the moon,' which is derived from the Sanskrit ‘chandra’ (moon) and ‘kanta’ (beloved).
Chemical composition of Moonstone
Moonstone is a potassium silicate member of the Feldspar group, a name derived from the German ‘feldt spat,' meaning ‘field stone’ after its capacity to enrich soil with plant nutrients. Feldspar is a mineral family especially known for gems with beautiful optical phenomena such as adularescence, aventurescence and iridescence . Its two subgroups are the plagioclase group and the potassium group. Distinguished by their calcium and sodium content and ratio, the plagioclase group includes most gem varieties. Gems in the potassium group share the same Chemical composition, but are distinguished by their crystal structure. One important thing to remember is that many Feldspar gems look similar, often confusing even gemologists due to their similar chemical compositions. Moonstone, for example, is of the potassium Feldspar group, Moonstone is closely related to Labradorite and Sunstone
A rare variety of Moonstone: Rainbow Moonstone.
Moonstone occurs commercially in a few isolated deposits in Brazil, Myanmar, the European Alps, India, Madagascar, Sri Lanka, Tanzania and the U.S., making it far rarer than many better known gemstones. Sri Lanka is famous as the main producer of superior quality Moonstones, almost transparent with a strong blue sheen. The majority of Moonstones extracted in Sri Lanka are sourced in the famous mines in Meetiyagoda in the south of the island, it is also mined at Dumbara, Tissamaharama and Imbulpe. Although Meetiyagoda has been mined for more than 50 years and only very few active deposits remain. Therefore, while this gemstone belongs to the most abundant minerals on Earth, gem quality stones are very rare. Moonstone from Tanzania is a relatively new variety, obtained from the Arusha region where Tanzanite is also mined.
The history of Moonstone
Many myths and legends feature this marvelous gemstone, starting with ancient India, where their four-armed moon goddess was believed to wear a Moonstone on her forehead, representing the moon itself. By superstition and due to its unique colors, it was believed that owning a Moonstone could attract beneficial divine influence. Moonstone was also very popular and sought after in the Western world; the ancients believed it was composed of tiny parts of the moon itself, and that its light was drawn from a positive divinity present within the gem. The Romans thought Moonstone’s appearance changed with the waxing and waning of the moon, even believing their moon goddess, Diana, was pictured in every Moonstone. A medieval legend states that a Moonstone would grant the wearer powers of divination. Forever a feminine and ‘Goddess’ stone, in mythology, divination was usually a feminine trait, so much so that during antiquity men used to meditate with a Moonstone in their mouths to see the future.
Moonstone’s mythology also makes numerous references to its ability to influence that most powerful and positive of all emotions, love. As a symbol of the ‘third eye,' Moonstone is said to balance Yin and Yang, protect against epilepsy, and improve recollection. In crystal therapy, the gem is said to help men get in touch with their feminine side.
Properties of Moonstone
Moonstone exists in a large variety of colors, including brown, colorless, green, gray, pink, rainbow, white and yellow. It has a luster that shifts from silver to blue, from semi-translucent to translucent, and often displays a high degree of luster. The most sought after examples of Moonstone display an intense blue luster, which slides off the surface of the gemstone depending on the viewing angle, with high purity and a colorless base. In general, the more intense the blue luster and the more transparent the Moonstone, the greater its value. Adularescence is the true magic of Moonstone, and as its key property determines a significant portion of its value.
Varieties of Moonstone
Rainbow Moonstone is a variety of Moonstone with the same Chemical composition as Labradorite Feldspar, which displays a marvelous bright blue adularescence along with iridescence which diffracts white light into its spectral components. Extracted primarily in Sri Lanka, Rainbow Moonstone generally has exceptionally clear crystals.
Labradorite owes its name to the Labrador peninsula in Canada, where it was originally discovered. It is a plagioclase Feldspar that is mined in China, India and Madagascar. Labradorite is available in transparent specimens (usually red, orange, yellow or colorless) as well as smoke gray varieties that show a striking metallic colored iridescence, aptly called labradorescence.
Sunstone is a plagioclase Feldspar that is typically yellow, pink, orange, red or colorless. Sunstone’s most important attribute is its aventurescence, the beautiful glittering sunlight effect caused by tiny metallic inclusions. Predominately mined in India, Madagascar and the U.S., Sunstone was once coveted for its purported ability to guide its wearer through the journey of life.
Care for Moonstone
Moonstone, like Rainbow Moonstone, Sunstone and Labradorite, can be subjected to steam cleaning, but not ultrasound cleaning.