Nephrite

Nephrite is one of the two minerals traditionally called jade, the other being jadeite. It is a calcium-magnesium-iron amphibole forming a dense felt of interlocking fibrous crystals, which makes it one of the toughest natural materials known despite only moderate hardness.

Nephrite typically displays muted greens ranging from creamy 'mutton fat' white to deep spinach green, colored by iron. Its smooth, waxy luster and resistance to breakage made it the favored material for tools, weapons, and ritual objects across many ancient cultures, long before jadeite was widely worked.

Major sources include China, Russia (Siberia), Canada (British Columbia), New Zealand, and Wyoming.

Nephrite forms through metasomatic and metamorphic processes, typically where serpentinite or ultramafic rocks react with silica-rich fluids, or where dolomitic marbles are metamorphosed. These reactions produce the dense, fibrous tremolite-actinolite aggregate that defines nephrite.

The interlocking microscopic fibers grow in contact and reaction zones, often at the boundaries between very different rock types. Boulder and alluvial nephrite is recovered from rivers that have eroded these source zones, as in New Zealand's South Island where Maori pounamu is gathered. Other important deposits occur in Siberia, British Columbia, Xinjiang in China, and Wyoming.

Nephrite is tough, dense, and cool to the touch, with a smooth waxy to greasy luster and a slightly fibrous, splintery fracture. Its colors are typically soft and somewhat cloudy rather than vivid, often with subtle mottling or banding.

It has a hardness of about 6-6.5 and a white streak. Distinguish it from jadeite, which is slightly harder, denser, and shows a granular 'orange peel' polish rather than a fibrous texture. Serpentine 'new jade' is much softer and easily scratched, while glass imitations feel warmer and may contain bubbles. Nephrite's extraordinary toughness, resisting chipping under a knife, is a key clue.

Nephrite has been carved for at least 6,000 years into tools, weapons, ornaments, and ceremonial objects. Today it is used for jewelry, beads, bangles, carvings, and decorative items, with fine 'mutton fat' white and spinach green especially prized.

In Maori culture, pounamu (nephrite) holds deep spiritual and ancestral significance and is fashioned into hei-tiki pendants and weapons. Chinese artisans have prized nephrite for millennia as a symbol of virtue and status. Metaphysically it is linked to protection, healing, and good luck, though such claims are not scientifically supported.