Serpentine

Serpentine is hydrated silicate of magnesium which is a green, yellowish-green, bluish-green in color with whitish cloudy patches.

Then name serpentine refers to a group of predominantly green minerals that occurs in mases of tiny Intergrown crystals. The two main types used in jewellery are bowenite (translucent green or blue-green) and also the rarer williamsite (translucent, oily green, veined or spotted with inclusions). They may be carved, engraved, or polished. Various marbles also contain serpentine veins.

Due to the low hardness of serpentine 2.5, exception with bowenite having 4 - 6 hardness, it can easily be scratched by copper coin, window glass, knife blade and steel which have higher hardness than serpentine. Therefore it is generally not preferred to use in day to day life.

Serpentine is a good simulant for nephrite (jade) but due to low hardness and lustre it can be separated from nephrite. Hardness is always directly proportional to lustre.

Bowenite is found in New Zealand, China, Afghanistan, South Africa, and United States; Williamsite occurs in Italy, England and China.

Serpentine Properties

Chemical Composition: 
Mg3Si2O5(OH)4 + Ni; Hydrated Silicate of Magnesium.
Colors / Varieties: 
  • Bowenite: yellow-green, deep green, bluish green
  • Williamsite: green with whitish veins of brucite
  • Ricolite: fine grained, with banding
  • Satelite: fibrous grayish to greenish blue
Crystal System / Forms: 
Monoclinic System / Cryptocrystalline aggregates.
Hardness: 
2.5; Bowenite: 4 - 6
Specific Gravity: 
2.44 - 2.62; Bowenite: 2.58 - 2.62
Cleavage / Fracture: 
None / Fibrous.
Optic Character: 
Aggregate (A.G.G.)
Lustre: 
Vitreous to waxy
Refractive Index / Birefringence: 
Range: 1.530 - 1.570, usually at 1.560
Pleochroism: 
None.
Dispersion: 
None.
Magnification: 
Whitish cloudy patches, octahedral crystals of magnetite / chromite.
U.V. Fluorescence: 
Williamsite may glow weak whitish green in longwave.
Spectrum: 
Bowenite bands at 492nm & 464nm.
Cause of Color: 
Iron, chromium, nickel.
Treatment (Enhancement): 
Simulants (with separation tests): 
Feldspar (lustre, hardness, structure, phenomena), Chalcedony (lustre, hardness), Marble (structure, birefringence), Jade (lustre, hardness, R.I., S.G.), etc.
Geological Occurrence: 
In varied deposits, in basic and ultrabasic rocks.
Sources: 
India, Pakistan, New Zealand, China, U.S.A. (California), etc.
Cuts & Uses: 
Cabochon, beads, cameos, intaglios, carvings, tablets.