Jadeite, NaAlSi₂O₆, is a semi-precious gemstone, a member of the inosilicate (chain silicate) family and the pyroxene group. It has a single chain structure (see highlighting features below) with infinite length chains along the c axis. Adjacent tetrahedral chains are inverted, thus providing relatively large sites for charge-balancing cations. Other cations, in this case sodium, balance leftover charges from the chain structure and holds the chains together.

Distribution

Jadeite is one of two minerals commonly called “jade”, the other being nepheline. The color of jadeite can range from bright apple green through blue-green to dark green. Black, white, yellow, and pink colors are also possible. It commonly occurs in compact, hard masses. Botryoidal forms sometimes occur. Jadeite is found only in metamorphic rock, where it is a replacement for nepheline or albite. It generally forms under high pressure and moderate temperatures, hence its occurrence in subduction zones. Significant deposits are found in California, Japan, the Alps, and other areas around the Pacific Rim. Jadeite is found in serpentine with deposits in Upper Burma as well as in the US. Jadeite is a semi-precious and ornamental stone and has been prized for its beauty and its durability for many centuries.

Cameron, M., S. Sueno, C.T. Prewitt, and J.J. Papike. 1973. High-temperature crystal chemistry of acmite, diopside, hedenbergite, jadeite, spodumene, and ureyite. American Mineralogist 58:594-618.