Jade is a name shared by two distinctly different minerals - Nephrite, a calcium magnesium silicate, and jade, a sodium aluminium silicate. Both have monoclinic crystal systems and are exceptionally tough stones, a trait caused by their finely interlocked and strongly bonded crystal structures.
The name Jade is derived, rather accidentally, from the Spanish term pier de jade ( or lapis nephrictus in Latin), meaning ístone of the loiní Where the term was misprinted in a French translation, it became pierre le jade.

The first Jade arrived in Europe from Mesoamerica, brought back by the conquistadors. During the seventeenth century, when Jade supplies from the Americas had diminished, Chinese carving of similar-looking stone labeled Nephrite, from the Latin, and it was later discovered that these were different materials from the original American Jade.
However, Burmese stones entering the marketplace in the mid-1800s were found to be the same as the original America Jade, and both of there were called Jadeite.
Today both types of stone are traded as Jade.

(For New Jade (Serpentine) please scroll down the page or visit the S/T/U section)