Serpentine broadly includes a number of minerals forming a polymorphic group. Though the structure of these minerals is different, their chemistry is basically the same. It is the foremost mineral forming rocks, and forms a constituent of numerous weather igneous rocks and metamorphic rocks. It often imparts a green color to the rocks. So, the majority of rocks in green color is likely to contain serpentine to some extent.
Mg3 (OH) 4 (Si3O5)
Derivation of Name
The expression “Serpentine,” is derived from “serpentyn,” from Medieval Latin serpentīnum pointing to the snakelike outline of these minerals.
It is typically found all along the axes and crests of huge folds like the chain of Alpine mountains and island arcs. It usually occurs in distorted peridotites, pyroxenites or dunites. Serpentinite is a rock that mainly comprises of serpentine.
Serpentine can acquire a high sparkle and is occasionally utilized as a decorative stone.
Prominent occurrences include Val Antigorio, Italy; Switzerland, Russia, Rhodesia, Quebec, Canada and North Carolina, Rhode Island, Arizona and California, in the USA.
They have slight differences which are difficult to distinguish in small samples. Yet, the Chrysotile minerals are more prone to forming serpentine asbestos, whereas at times Lizardite and Antigorite form cryptocrystalline masses with a lamellar or micaceous character. Asbestos has fire retarding characteristics, prompting its use in producing brake linings and as a fire retarding cloth. However, use of asbestos for such applications has been replaced by other materials due its association with cancer.
The structure of Serpentine comprises of layers of silicate tetrahedrons coupled to sheets. Between the layers of silicate there are layers of Mg (OH) 2, which are set up in the mineral Brucite and thus named as Brucite layers. The stacking is imperfect, causing the layers to bend. In the majority of serpentine, the Brucite and Silicate layers are further mixed and produce complicated sheets. In the case of asbestos, the Silicate and Brucite layers bend into tubes that produce fibers.
It occurs in yellow, golden, olive green, brown or black color.
Mohs Scale Hardness
3 - 4.5