Hydrated silicate oi magnesium. Serpentine can contain three polymorphsz lizardile. chrysctile and antigorite. At least two ot the three are usually present. Gemologists recognize serpenlirie as a species. Ililinerslogisls recognize it as e group name. geologists as the rock type serpentinite. It is so named because of its resemblance to the reticulations ol snakeskin.
Crystal system Orthorhombic tor lizardite; monoclinic tor antigorite and chrysotile.
Appearance Minerals of the serpentine group occur in microcfyﬁtalline veins (more rarely. masses) of trarlslucent, waxy appearance. of a greenish gray to grayish white. or green color, in clerk green or blackish colored rocks. i.e- serpentinites.
Physical proportion The densities within the group vary trom 2.3-2.5. The hardness also varies from 2-3. but serpentirlite itsett can be as hard as 5. As is olten the case with microcryslalline materials, only one retractive index can normally be established; it is usually about 1 .55-1.56.
Genesis It is a product of regional metamorphism. in a strongly aqueous environment. of magnesium-rich minerals. mainly olivine. but also pyroxenes and amphiboles,
Occurrence lt is a very common mineral.
The massive varieties of serpentinite are particularly appreciated by gemologists when they have a definite, pleasing color, and are then called simply serpentine or maybe "serpentine jade." The term jade is a misnomer, but it is understandable because, as in the case of jadeite jade and nephrite jade, it relates to the uses made of these materials as a result of certain properties they possess, rather than to their mineralogical status.
Appearance it is translucent, waxy, usually greenish white to soft pale green. Sometimes, groups or rows of small, striking, whitish cloud shapes are visible on the inside. The yellow-green to definite green varieties are less common. Multicolored pieces are also found, with light green tc green, yellow-green, or brown patches. Serpentine is mainly used for the carved figurines or decorated vases up to eight to twelve inches high, typical of Chinese art. Being fairly tenacious (although less so than jade). it is suitable for the fashioning of the classic vases with hanging chains carved from a single piece of stone. Very elaborate compositions are often found as well, such as leafy branches, groups of birds, and flowering shrubs. Skillful use of different patches of color increases the value of such pieces. But serpentine is used still more often for the large-scale production of low quality items, because it is less costly than true jade and easier to work, being less hard. Typical of this type of work are small elephants or oriental divinities. The less common, green, yellow—green or yellow varieties are also rounded, polished, and made into beads for necklaces and bracelets.
Distinctive features When the color is greenish white. with a waxy translucence and the characteristic white cloud formations just below the surface, it is easily recognizable at first sight. It differs from jadeite iade in having a lower density and hardness. It is mainly distinguished from nephrite jade, which is normally a bit less translucent and less waxy, by its density. while the difference in hardness is less clear (the serpentine used for ornamental purposes has a hardness range of 4.5 to 5.
Occurrence Most serpentine used for ornamental purposes comes from England, New Zealand, Korea, China, and the United States.
Value Its value is slightly lowerthan that of nephrite jade. It is therefore quite high for finely crafted objects, possibly fashioned from multicolored pieces, but distinctly low for mass-produced items.
Simulants and synthetics Oriental-style figurines have been produced from a light green, translucent, waxy-looking plastic. These are highly deceptive at first sight, looking -tel’! muﬂh like Serpentine. Their density is much lower, but it is not always easy to detect without proper measurement. Serpentine has not been produced synthetically.