Jadeite & Nephrite

Jadeite is a sodium aluminum silicate and nephrite is a calcium magnesium silicate. While nephrite is considered a lesser form of jade today, it was the form of jade that was first introduced to Europe from the new world.

Jadeite:
NaAlSi₂O₆

Hardness--6.5 to 7
Poor cleavage in two directions at 90 degrees (never seen in massive specimens)
Uneven fracture
Vitreous, greasy luster
Translucent
Color--variable shades of green; also yellow, pink, violet, orange, brown, white, and black

Jadeite usually forms as a massive granular, less commonly forming prismatic or tabular crystals. It is generally found in high pressure metamorphic rocks. Jadeite is also very tough, tougher than steel in fact.

Nephrite:
Ca(Mg,Fe)₅Si₈O₂₂(OH)₂

Hardness--
Perfect cleavage in 2 directions at 60 and 120 degrees
Uneven/splintery fracture
Vitreous luster
Transparent to translucent
Color--creamy white to green, pink and purple varieties have been found in Wyoming

Nephrite is considerably more abundant than jadeite. It forms as a massive, but can also be very fibrous. It is sometimes used as an asbestos, but more commonly as an ornamental stone for carvings and as a semi-precious to precious stone for jewelry. It was also used to make stone tools because of its strength. Like jadeite it is also tougher than steel.

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