Moonstone

Moonstone owes its name to the white, almost magical shimmer that resembles moonshine. Blue-whitish light glides over the surface when the stone is cut cabochon. Gemologists call this phenomena adularescence, which originates from the interior structure of the gemstone in scales or lamellas. Incoming rays of light are refracted inside the stone and scattered, creating a unique play of light, which makes Moonstone so special and coveted. Moonstone is the most well known potassium feldspar of the orthoclase species. A combination of orthoclase and albite arranged in layers cause the lovely sheen. Moonstone is fairly soft, 6-6.5 (Mohs scale) and sensitive to pressure. In Arab countries women often sew moonstone into their garments, because it's considered a symbol of fertility.

Moonstone is the birthstone for those who are born in June. Moonstone from Sri Lanka, the classical country of origin for Moonstone, shimmers pale blue on an almost transparent ground. Specimens from India show cloudlike plays of light and shade on beige brown, green, orange, or simple brown background. They do come as well in blue and peach, smoke and champagne colored, or in black and reddish. Moonstone is fairly soft, 6-6.5 (Mohs scale) and sensitive to pressure. Blue Moonstones in fine qualities are becoming increasingly short in supply and push up the prices accordingly. Really top quality fine blue Moonstone show an incredible "three-dimensional" depth of color, which one will see clearly only when playfully tilting the stone and moving it. The more transparent the moonstone, the more valuable it is. Moonstone cat's eye and multi-rayed star moonstone are known, but rare. Classically moonstones are always cut as cabochons. Here the appropriate height of the stone is essential to display the desired light reflection. The cutter must also bear in mind to locate the crystal axis exactly in the zenith of the stone, because only then the desired effect of light play will be achieved.

Deposits are found in Brazil, India, Madagascar, Myanmar, Sri Lanka and the United States.

There is no treatment known which enhances moonstone quality. This gemstone was extremely popular in the times of "Art Nouveau", more than 100 years ago. It used to decorate a striking amount of pieces of jewelry created by the famous French master-goldsmith René Lalique and his contemporaries. These pieces are usually only found in a museum or in safeguarded collections.

Moonstone Gemology
Species: Feldspar
Color: Colorless, yellow, pale sheen
Chemical composition: KalSi3O8 potassium aluminum silicate
Crystal system: Monoclinic, prismatic
Hardness: 6-6.5 (Mohs scale)
Specific gravity: 2.56 - 2.59
Refractive index: 1.518 - 1.526
Birefringence: -0.008
Color of streak: White,
Absorption spectrum: Not diagnostic
Fluorescence: Weak; bluish, orange

Moonstone is the birthstone for those who are born in June.

In Antiquity, as well as in the Middle Ages people believed that the cosmos is reflected in gemstones. The moonstone is assigned to the planets Neptune and Venus.

The healing powers of gems remain a controversial issue, but are mentioned for centuries by healers, shamans and medicine men. Whether it's a fact or a placebo effect doesn't matter, if it helps. The safest approach is to wear the gemstone in skin contact to the troubled part of the body. Moonstone is said to be of help for headaches and backache.