Nephriitin

Nephriitin is a mineral compound, specifically a silicate, belonging to the amphibole group. Its chemical formula is generally expressed as Ca2(Mg,Fe)5Si8O22(OH)2, indicating it is a calcium magnesium iron silicate hydroxide. Nephriitin is one of the two primary mineral forms of jade, the other being jadeite. It is a tough, fibrous mineral often found in metamorphic rocks. Its color can vary widely, ranging from white and green to black and brown, with shades of green being the most commonly associated with its use as a gemstone.

The physical properties of nephriitin contribute to its historical significance and widespread use. It is known for its exceptional toughness, which makes it resistant to breaking and chipping, even when subjected to significant force. This property, combined with its attractive appearance, led to its veneration and use by ancient cultures, particularly in East Asia, for tools, ornaments, and religious objects. Nephriitin is typically found in metamorphic terranes where serpentinite rocks are present. Large deposits have been historically significant in regions like China, New Zealand, and parts of North America. Its fibrous structure gives it a characteristic granular or felted texture when viewed microscopically. While both nephriitin and jadeite are classified as jade, nephriitin is generally softer and less dense than jadeite.