White Jade (Nephrite)

Hardness: 6-6.5 on Mohs scale. Color: Translucent to opaque white, sometimes with a very pale green or yellowish tint. Luster: Vitreous to greasy. Crystal Structure: Monoclinic, typically found in a massive or fibrous aggregate form, not distinct crystals. Cleavage: None, but exhibits tough, splintery fracture due to intergrown fibrous crystals. Specific Gravity: 2.9-3.1.

Nephrite jade forms as a replacement mineral in metamorphic rocks or through metasomatic alteration of ultramafic rocks. It typically originates in serpentinite belts or at contact zones where igneous intrusions meet dolomitic limestones. The process involves low-grade regional metamorphic conditions or contact metasomatism. Geological age can vary widely depending on the specific deposit, ranging from hundreds of millions to tens of millions of years old.

Prized for millennia in jewelry, carvings, and ornamental objects, especially in East Asian cultures. Its exceptional toughness makes it suitable for intricate carvings and tools, though it is less commonly used for tools today. In ancient times, it was used for weapons and implements. Today, it is predominantly used for decorative items, pendants, beads, and sculptures.

Nephrite and Jadeite are the two distinct mineral species classified as "jade." Nephrite is generally softer, sometimes has a greasier luster, and often occurs in more subdued colors compared to jadeite. Its extreme toughness made it historically valuable for tools and weapons, as it is very resistant to breaking. White nephrite, often called 'Mutton Fat Jade' in China, is highly valued for its pure white color and smooth, greasy luster.

In the field, nephrite jade can be identified by its characteristic toughness (it's very difficult to break), waxy or greasy luster, and typically translucent to opaque appearance. It often feels smooth and cool to the touch. It's commonly found in metamorphic rock environments, particularly in areas with serpentinite. Major deposits are found in China (especially Xinjiang province), New Zealand, Canada (British Columbia), Russia, and the United States (Wyoming, California, Alaska).