[Geography Notes] on Jadeite Pdf for Exam

Jadeite is a pyroxene mineral with the chemical formula NaAlSi₂O₆. It has a single axis. Depending on the composition, it has a Mohs hardness of 6.5 to 7.0. The mineral has a specific gravity of about 3.4.

The name jadeite is derived from the Spanish phrase “piedra de ijada,” which means “stone of the side”. The term nephrite is derived from the Latin version of the name, lapis nephriticus, which is a different mineral from the common name jade.

Jadeite Stone Chemistry

Other pyroxene end members that form solid solutions with jadeite include augite and diopside (CaMg-rich endmembers), aegirine (NaFe endmember), and kosmochlor (NaCr endmember). Omphacite is a type of pyroxene that contains both the jadeite and augite endmembers. Jadeite forms in metamorphic rocks under high pressure and relatively low temperature. Albite (NaAlSi₃O₈) is a common mineral in the Earth’s crust with a specific gravity of about 2.6, which is significantly lower than that of jadeite. Albite degrades under increasing pressure to form the high-pressure assemblage of jadeite and quartz.

Jadeitite refers to rocks that are almost entirely composed of jadeite. Jadeitite appears to have formed from subduction zone fluids in association with serpentinite in all well-documented occurrences. Jadeitite is resistant to weathering, and boulders of jadeitite formed in serpentine-rich environments can be found in a variety of environments.

Jadeite Stone Colour

The colour of jadeite typically ranges from white to pale apple green to deep jade green, but it can also be blue-green (as in the recently rediscovered “Olmec Blue” jade), pink, lavender, and a variety of other rare colours. Chloromelanite is a dark green to black mineral. The presence of trace elements such as chromium and iron has a large impact on colour. Its transparency ranges from opaque to nearly clear. Colour and translucency variations are common even within a single specimen.

Where is Jadeite Found?

Jadeite has been found in California, the United States, Myanmar, New Zealand, Guatemala, and Itoigawa, Japan; other jadeite locations include Kazakhstan, Russia, British Columbia, Canada, Italy, and Turkestan.

What is Imperial Jade?

Originally, it was assumed that all jade objects were made of the same material. However, in 1863, a Frenchman named Alexis Damour discovered that “jade” could be separated into two minerals: jadeite(imperial Jade) and nephrite.

The mineral compositions of jadeite and nephrite are markedly different. Nephrite is a magnesium-rich amphibole, whereas jadeite is aluminium-rich pyroxene. However, in the eyes of the average person, the two minerals have very similar physical properties.

Physical Properties of Jadeite and Nephrite

What is Jadeite Used for?

Over 180 axe heads made from jadeitite quarried in northern Italy during the Neolithic era have been discovered across the British Isles. Due to the difficulty of working this material, all of the axe heads found are thought to be non-utilitarian and to have represented some form of currency or be the products of gift exchange.

Many jadeite beads and axe heads, as well as the remains of Neolithic jadeite workshops, have been discovered in Itoigawa, Japan. These beads and axes were traded throughout Japan and the Korean Peninsula and were made by the Itoigawa region’s oldest known jadeite-using culture.