Jade

What we call 'jade' is actually two completely different minerals that happen to look similar: jadeite (a pyroxene) and nephrite (an amphibole). They weren't distinguished as separate minerals until 1863.

Nephrite forms in metamorphic environments when calcium and magnesium-rich rocks (like serpentinite) are altered by heat and pressure. Its extraordinary toughness - greater than steel - comes from its microstructure: interlocking bundles of microscopic fibrous crystals that resist fracture the way a rope resists breaking. This is why nephrite was prized for tools and weapons before metallurgy.

Jadeite forms under extreme conditions - high pressure but relatively low temperature - typically in subduction zones where oceanic crust dives beneath continental plates. These conditions are geologically rare, which is why gem-quality jadeite is found in very few places on Earth. The finest 'Imperial jade' - translucent, vivid emerald green, colored by chromium - comes exclusively from Myanmar and commands prices exceeding $3 million per kilogram at auction.

Jade's most distinctive property is its exceptional toughness - it's harder to break than any common gemstone, including diamond. A genuine jade piece rings when tapped and feels dense and cool in the hand. Jadeite (SG 3.30) is noticeably denser than nephrite (SG 2.95).

Distinguishing jadeite from nephrite without gemological equipment is difficult. Jadeite tends to have a slightly more vitreous, glassy luster and can achieve brighter, more saturated colors, especially green. Nephrite typically has a more oily or waxy luster and appears in more muted tones. The many jade imitations (serpentine, aventurine, chrysoprase, glass) make laboratory testing essential for valuable pieces.