Rocks that consist almost entirely of jadeite are called jadeitite.
In all well-documented occurrences, jadeitite appears to have formed
from subduction zone fluids in association with serpentinite, as
discussed by Sorensen et al. (2006).
Jadeitite is resistant to weathering, and boulders of jadeitite
released from the serpentine-rich environments in which they
formed are found in a variety of environments.
Jadeite's color commonly ranges from white through pale apple
green to deep jade green but can also be blue-green (like the
famous and recently rediscovered "Olmec Blue" jade), pink,
lavender, and a multitude of other rare colors. Chloromelanite
is a very dark green to black variety. Color is largely affected
by the presence of trace elements such as chromium and iron. Its
translucence can be anywhere from entirely solid through opaque
to almost clear. Variations in color and translucence are often
found even within a single specimen.
Currently, the best known sources of gem quality jadeite are
California, Myanmar, New Zealand and more recently Guatemala;
other localities of jadeite include Kazakhstan, Russia,
British Columbia, Alaska, and Turkestan.
Jadeite is one of the minerals recognized as the gemstone
jade. The other is the green amphibole, nephrite. Jadeite
from the Motagua Valley, Guatemala is the stone used by the
Olmec, Maya peoples, and the indigenous peoples of Costa Rica.
Typically, the most highly valued colors of jadeite are the
most intensely green, translucent varieties, though
traditionally white has been considered the most valuable
of the jades by the Chinese, known for their carefully
crafted jade pieces. Other colors, like "Olmec blue"
jade, which is characterized by its deep blue-green,
translucent hue with white flecking, are also becoming
more highly valued because of its unique beauty and
historical use by the Mesoamerican Olmec and also in
Costa Rica ; however, this variety was only recently
rediscovered and is only being minimally exploited by
native Guatemalans. It is thus difficult to obtain
and as yet too rare and little known to have attained
great value as a gemstone. When purchasing jade, quality
is determined by the degree of translucence, cleanness of
color, and purity of color. Occasionally, other minerals
like serpentine or quartz are sold as jade but the
difference can be determined by cleavage and hardness.