Serpentine rough

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.

Cause of Color :

Iron, chromium, nickel.

Chemical Composition :

Mg3Si2O5(OH)4 + Ni; Hydrated Silicate of Magnesium.

Crystal System / Forms :

Monoclinic System / Cryptocrystalline aggregates.

Cuts & Uses :

Cabochon, beads, cameos, intaglios, carvings, tablets.

Dispersion : None.
Hardness : 2.5; Bowenite: 4 - 6
Lustre : Vitreous to waxy
Magnification :

Whitish cloudy patches, octahedral crystals of magnetite / chromite.

Optic Character :

Aggregate (A.G.G.)

Pleochroism : None.
Refractive Index / Birefringence :

Range: 1.530 – 1.570, usually at 1.560

Simulants (with separation tests) :

Feldspar (lustre, hardness, structure, phenomena), Chalcedony (lustre, hardness), Marble (structure, birefringence), Jade (lustre, hardness, R.I., S.G.), etc.

Sources :

India, Pakistan, New Zealand, China, U.S.A. (California), etc.

Spectrum :

Bowenite bands at 492nm & 464nm.

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