The term 'Jade' has its roots in the French language, but its origin traces back to the Spanish phrase 'piedra de hijada,' meaning "lion stone." The Spanish introduced the stone to Europe, where a translation error led to the French term 'pierre de jade.'

Nephrite, derived from the Greek word "nephriticus," meaning "kidney stone," reflects the historical belief that the mineral had curative properties for kidney stones.

The word "Jade" is now applied to two distinct minerals: nephrite and jadeite. Both minerals share a name and have similar properties. However, their mineral compositions, appearances, and geographical origins differ.

Both are renowned as ornamental stones, celebrated for their toughness, rich cultural history, and unique aesthetic qualities.

Nephrite Formation and Identification

Formation

Nephrite is a silicate mineral that forms under specific geological conditions—when rock undergoes metamorphism at high pressure but relatively low temperature. Various tremolite-actinolite minerals belong to the amphibole group and are primarily composed of calcium, magnesium, iron, and silicate.

Nephrite's structure comprises fibrous crystals, giving it a grainier texture than jadeite. Because the minerals within the crystal vary, nephrite can show a wide range of colors, including shades of green, white, red, brown, and black. The most prized nephrite is an intense, vibrant green, often exhibiting patterns and inclusions that enhance its visual appeal and value.

When polished, nephrite has a smooth, often waxy, fibrous texture, which adds to its desirability for sculptures and carving intricate designs. Though slightly softer than jadeite, nephrite jade is a durable mineral suitable for various lapidary projects. With a hardness of 5 to 6 on the Mohs scale, it cannot be scratched by a steel knife blade.

Identification

Ornamental nephrite and jadeite are commonly found in massive forms or as granular aggregates. Visually distinguishing between the two can be challenging. Up until the 19th century, they were often considered the same mineral.

To differentiate nephrite from jadeite, specialized tests such as petrographic, geochemical, or X-ray diffraction analyses are typically required. However, for a more practical, home-based approach, you can distinguish them by measuring their specific gravity. Additionally, the color and massive structure of the specimen can aid in identification.

Rocks and Minerals Similar to Nephrite Jade

Many rocks and minerals resembling nephrite jade can be identified through their physical properties, such as hardness and density, or by X-ray diffraction analysis.

These include green jasper, serpentine, serpentinite, amphibolite, metadiabase, leucocratic granite, epidote, and fuchsitic quartzite.

Distinguishing Keys

Jasper: Harder than nephrite.
Metadiabase, amphibolite, and leucocratic granite: Have a granular structure.
Quartzite: Exhibits conchoidal fractures, which are notably different than nephrite.
Epidote: Has perfect cleavage and pistachio-green color.
Serpentinite: Relatively soft and can often be easily scratched with a knife.

Value of Raw Nephrite

Nephrite is generally less expensive than jadeite. Its value depends on factors such as origin, color, translucency, and quality, typically ranging from $1 to $10 per gram. For the most accurate and up-to-date information on market prices, consult reputable gemstone dealers.

Lapidary Use

Nephrite jade is easy to tumble, shape, and polish, making it popular for sculptures, jewelry, carvings, and various decorative items.

Cautions: Nephrite contains asbestos, and its dust can be harmful when cutting or carving. Wear a respirator for your safety and work with wet grinding and mopping to control the dust.

Cultural and Historical Significance

Nephrite has been highly valued in various cultures for thousands of years. It has been used as ceremonial objects, jewelry, weapons, and tools such as knives, hammers, or fish hooks.

China: Jade has been associated with virtues such as purity, virtue, and immortality.
Native American Cultures: Jade has been used for tools, ornaments, and ceremonial objects.
Pacific Northwest: Jade carving has been an art form among Indigenous peoples, with intricate carvings often depicting animals, symbols, and spiritual figures, reflecting the rich cultural heritage of the region.

Nephrite Jade Occurrences

Nephrite Jade has been discovered in diverse locations worldwide, with notable sources including China, Russia, New Zealand, Canada (Alberta, Newfoundland, and Labrador), and the United States (Alaska, California, Oregon, and Wyoming).

British Columbia is the primary source of modern lapidary high-quality nephrite in Western Canada. Quebec in Eastern Canada also has some nephrite deposits.

Where to Find Nephrite?

Pacific Ocean Shoreline: Beach-worn nephrite is common from Alaska to California, with notable locations along the South Oregon Coast and Central California Coast.
Central Wyoming: Known for its exceptional quality, considered some of the finest nephrite in the world. Look for nephrite in hills and stream gravels on public lands. Refer to the Rockhounding Wyoming book for more information.