Serpentine is the name used for several different aggregate structures that are usually green, yellowish-green, or brownish-green. The finest serpentine is cut as cabochons for gemstones, or carved into decorative objects. Serpentine is sometimes confused with jade, but jade is much harder, tougher and has a less greasy luster than serpentine.
Two basic structures for serpentine are usually distinguished. They are antigorite (leafy serpentine) and chrysotile (fibrous serpentine). The chrysotile minerals are more likely to form serpentine asbestos, while antigorite forms cryptocrystalline masses, sometimes with a lamellar or micaceous character. Since asbestos fibers are a health hazard, only the antigorite form is used for gemstones or carvings.
Most serpentine is opaque to translucent, with a Mohs hardness rating ranging from 2.5 to 5.5. Antigorite tends to be the harder variety. Serpentine is fairly light, with a density of 2.44 to 2.62, which is slightly lower than that of quartz. The luster of serpentine can be greasy, waxy or silky. Serpentine is known to be sensitive to acid.
A number of trade names have been introduced to refer to serpentine varieties, including bastite, bowenite, connemara, verd-antique and williamsite. You may also encounter terms such new jade, noble serpentine and precious serpentine. However the latter three terms are not used in gemology.
Serpentine varieties are found in many places in the world, including Afghanistan, Burma, China, New Zealand, the USA, Canada, the UK, Greece, Italy and Norway.
- First Published: November-08-2010
- Last Updated: August-04-2014
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