1. Chemical differences
The chemical differences between nephrite and jadeite are subtle enough to allow both to be called jade.
Chemically, nephrite and jadeite are different enough for mineralogists to place them in different categories. Nephrite is an amphibole. Amphiboles are complex silicate minerals with similar crystal structures that contain calcium, sodium, magnesium, aluminum, and iron atoms, or a combination of them. Jadeite is a pyroxene. Pyroxenes are common rock-forming minerals that contain calcium, sodium, magnesium, iron, or aluminum that usually occur in short crystals. These differences are minor enough to allow both nephrite and jadeite to be known in the marketplace by the generic trade term, jade.
2. Structural differences
Nephrite is made up of interwoven fibrous crystals and is even tougher than jadeite.
Nephrite and jadeite derive their toughness from slightly different structures. While jadeite’s structure is an arrangement of grainy crystals, nephrite is made up of fibrous crystals that interlock in a matted, tufted texture. These densely packed and interwoven fibers are extremely resistant to fracturing, even more than jadeite’s interlocking grains.
For centuries, nephrite was the only jade known to the Orient. Nephrite is still popular today, both as a less-expensive alternative to jadeite and as a beautiful ornamental stone. Unlike other jadeite alternatives, nephrite’s mineralogical properties are quite similar to jadeite’s.
3. Colour Differences
Colour is jadeite’s most important value factor. Because consumers
traditionally associate jadeite with the colour green, it surprises some people to learn that it comes in other colours as well—lavender, red, orange, yellow, brown, white, black, and gray. All of these colours can be attractive, but jadeite’s most desirable color is, in fact, a very specific intense shade of green known as Imperial.
Nephrite’s beautiful, earthy colours, combined with its toughness, make it ideal for carving. White is traditionally the most prized colour for nephrite carvings, and it was once reserved for royalty. From dynasty to dynasty over thousands of years, Asian nephrite carvings have delighted the imagination as well as the eye.
Words extracted from GIA-COLORED STONE-JADE
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