jade, jadeite, fei cui, nephrite, amber, quartz, tourmaline, coral, gems, Indian lapidary

Jade is a popular name for various tough, compact ornamental stones ranging in color from nearly white to deep green, long used in tools, ornaments, and decorative objects, but scientifically restricted to the minerals jadeite, nephrite, and the iron-rich jadeite variety chloromelanite. Though chemically distinct, jadeite and nephrite share many physical traits—both are hard, compact, usually fibrous, translucent, capable of high polish, and exhibit a characteristic sheen. Jadeite, a sodium-aluminum silicate of the pyroxene group, sometimes contains iron, calcium, and magnesium, with chloromelanite having up to 10% iron. Typically found as a massive aggregate of fibres or granules, jadeite has a hardness of about 7 and a specific gravity of 3.33, melting easily to a clear glass and resisting hydrochloric acid unless pre-fused. Its colors vary widely, though shades of white and green predominate, with prized tones like pale lavender and emerald green, the latter known as fei-ts’ui in Chinese. Nephrite, a calcium-magnesium silicate of the amphibole group, identical in composition to tremolite and actinolite but structurally different, is a dense mat of fine fibres, never found as discrete crystals. With a hardness of 6.5 and specific gravity around 3.0, it melts to a greenish glass and is acid-resistant. Its colors also vary but tend toward darker greens, with white more common than in jadeite, though rarely pure, and with occasional faint greenish, bluish, grayish, or pale yellow tones. The close resemblance between jadeite and nephrite has led to their common classification as jade, though accurate distinction often requires detailed chemical and microscopic analysis, especially when both occur together through metamorphic transformation. Despite jade’s ancient use, known in situ sources are few, with most material recovered from secondary deposits. The most studied jadeite locality is in Upper Burma’s Kachin region, while India and Tibet are said to contain jade but lack verifiable quarry evidence. Jadeite from Mesoamerica is distinctly different and may yet be found in situ. Nephrite is more widely distributed, with primary sources in the Kunlun Mountains of Turkistan, long known and studied, and occurrences in Siberia, Switzerland, France, Alaska, British Columbia, Washington, New Zealand, and New Caledonia. European finds have mostly been boulders, with confirmed in situ deposits only since the late 19th century. Jade’s toughness and beauty made it highly valued in prehistoric tools and ornaments worldwide, evident from finely made axes, adzes, and pendants found across Europe, Asia, and the Americas, with China, Central America, and New Zealand contributing iconic forms like the hei-tiki. China, above all, revered jade as the supreme precious material, used in ancient rituals and praised for its tactile and aesthetic qualities. The Chinese tradition emphasized carving, particularly in floral and symbolic motifs, often for imperial use, with designs reflecting strict sumptuary codes. India introduced the practice of embedding jade with gems, creating luxurious pieces during the Mongol empire, combining delicate carving with rubies, emeralds, and enamel. The artistic elegance of these and simpler forms highlights jade’s enduring appeal. Modern jade work continues, notably in Europe and Russia, with examples such as a Paris-cut paper knife from New Zealand nephrite and elaborate imperial Russian vases demonstrating the material’s ongoing artistic potential.