Jahar Mohara is Serpentine, a hydrous silicate of Magnesium [Mg6(Si4O10)X(OH)8 ]. This is also known as Green Marble in trade.
- Serpentine, Green Marble, Hindi
- Jaharamoharā, Telugu
- Salagrama silā, Urdu
- Zahar Mohra, Hajr-us-sum, Fad Zahr Madani, Hajrul-behr (N.F.U.M.)
Hydrous magnesium silicate
Origin and occurrence:
Jahar Mohara results from the alteration, either during metamorphism or by late-stage hydrothermal action at temperatures below 4000, of rocks rich in magnesium, containing olivine, pyroxene or amphibole. Magnetite usually accompanies this alteration. Some serpentine occurs as large rock masses generally referred to as serpentinites. Nickel in minor amount is generally present in Jahar Mohara. A little amount of Calcium, Iron and Aluminium may also be present.
In India, Jahar Mohara occurs mostly in metamorphic terrains of
Rajasthan, Karnataka, Jharkhand, Madhya Pradesh and Andhra Pradesh. In
Rajasthan, it occurs abundantly in Udaipur and Dungurpur districts.
: Crystalline, coarse grained, soapy feel, Colour
: Blackish green, Streak
: Colourless, Cleavage
: Perfect, Fracture
: Conchoidal, Lustre
: Greasy, Tenacity
: Tough, Transparency
: Translucent, Hardness
: 3.5 to 5, Sp. Gr.
: 2.5 to 2.7
Bi-axial, negative, weakly birefringent with R.I. 1.546 to 1.554 (Appendix- 2).
Effect of Heat:
Take about 1 g powdered sample of Jahar Mohara in open test tube. Heat the test tube at around 5000. The sample gets decomposed and gives off a little water.
Heavy metals and Arsenic
- Should contain not less than 30% magnesium oxide when analysed
by gravimetric method (Appendix-3.1.6).
- Should contain not less than 30 % Silica (SiO2), not less than 5% Ferric oxide (Fe2O3) and not less than 5% calcium oxide (CaO) when analysed by gravimetric method (Appendix -3.1).
: Jahar Mohara should not contain more than the stated limits for the following: - Arsenic = 2 ppm and Cadmium = 3 ppm (Appendix-3.2).
Other Elements :
May contain the following within ± 20% of the stated limits:- 0.15 % Nickel when analysed by Atomic Absorption Spectrophotometer (Appendix-3.2.2).
Shall not be used in formulations without subjecting it to śodhana.
[Ref. Rasatantrasāra Siddha Prayoga Sangraha, Part-1, Page 73 ]
i) Jahar Mohara : 1 part
ii) Go-dugdha : Q.S
Heat Jahar Mohara till it becomes red hot and dip in Go-dugdha or Amalaki rasa for 21 times.
Jahar Mohara is used in the form of pisti, the details of which are given in the monograph of pisti.