Jade is actually two separate gems: nephrite and jadeite. In China, a pierced jade disk is a symbol of heaven.
Two different gem materials can correctly be called jade. Jadeite is one of them, and the other is nephrite. Both are actually metamorphic rocks made up of tiny interlocking mineral crystals. These interlocking crystals make both gems exceptionally tough. Jadeite comes in a wide range of attractive colors: Many shades of green, yellow, and reddish orange, plus white, gray, black, brown, and lavender (often a light purple or light grayish violet color). The coloration is often streaked or mottled, giving jadeite gemstones an interesting visual texture that carvers can use to create imaginative and intriguing effects.
Nephrite is also accepted as jade in the international gem and jewelry industry. It ranges from translucent to opaque and can be light to dark green, yellow, brown, black, gray, or white. Its colors tend to be more muted than jadeite’s, and they’re often mottled or streaked.
Modern gemologists use the word “jade” as a generic term for both nephrite and jadeite. These gems have been linked throughout history. In fact, the term jade has also been applied to a number of gems and ornamental materials that resemble jade, and even some manmade equivalents resembling jadeite and nephrite.
BIRTHSTONES & ANNIVERSARIES
Jade is the official gem for the 12th anniversary.
WHY WE LOVE THIS GEMSTONE
INTERACTION WITH LIGHT: Jadeite’s structure scatters light. If properly cut, a white piece with a small green spot will make the gem appear completely green if lit from behind.
TOUGH, BUT NOT HARD: Not unusually hard for a gem, both jade types are extremely tough. Neolithic knives and axe heads were often made of nephrite.
MUSICAL JADE: Nephrite rings musically when struck. The imperial court in China had jade wind chimes designed to ring specific notes.
MINERAL: Jadeite and Nephrite
CHEMISTRY: NaAlSi2O6 and Ca2(Mg,Fe)5Si8O22(OH)2
COLOR: Green, white, orange, yellow, lavender, black
REFRACTIVE INDEX: 1.666 to 1.680 (+/-0.008) and 1.606 to 1.632 (+0.009, 0.006)
BIREFRINGENCE: Usually not detectable
SPECIFIC GRAVITY: 3.34 and 2.95
MOHS HARDNESS: 6.5 to 7 and 6.0 to 6.5