Renee Newman shared her expertise with the DCGIA members, providing a comprehensive guide to jade.
What it is, why it’s prized, and how it’s tested and valued.
Ancient cultures prized nephrite jade for being stronger than other stones. Making it ideal for tools, weapons and utensils without breaking or chipping. It also took and kept a sharp edge.
Jadeite is one of two gemstones recognized as jade. The other is nephrite. Jadeite jade and nephrite jade are each a rock, not a single mineral. While both are jade, there are significant differences between them. Jadeite jade is composed mostly of the pyroxene mineral jadeite and is harder than nephrite. Nephrite jade is composed primarily of actinolite and tremolite but its fibrous felt-like texture makes it a little tougher than jadeite.
Top quality jadeite is near to semitransparent, while the best nephrite is translucent. The lowest grades of jadeite and nephrite are semi-opaque.
Nephrite jade colors tend to be more muted and grayish except for black jade. Jadeite jade colors tend to be brighter. The color of jade together with its degree of transparency are key elements of value.
Jadeite Treatment Nomenclature:
“A” jade; natural untreated jadeite jade except for possible surface waxing
“B” jade; bleached, polymer-impregnated jadeite jade
“C” jade; bleached, dyed and polymer impregnated or simply dyed jade
Additionally, Renee provided some basic clues & tests for separating nephrite from jadeite jade, as well as imitation look-a-likes.
DCGIA thanks Renee for sharing her very informative presentation to our members.
Whether you are a jewelry professional or consumer you will find Renee Newman’s many Gemstone Books an indispensable resource.
Please include the tests used to distinguish nephrite from Jadeite.