Sang-e-Yashab: Nephrite Jade

Nephrite is one of the two minerals called jade, the other being jadeite. It is made of microscopic fibres of tremolite and actinolite, woven together like felt. That structure makes it one of the toughest natural materials in the world, so tough that it was used for tools long before it became jewellery. Its Urdu name, Sang-e-Yashab, simply means the jade stone.

Nephrite is most often a deep spinach green, coloured by iron, and also comes in olive, creamy white known as mutton-fat, grey and black. Sources include China, Siberia, Canada, New Zealand and Central Asia. Mughal craftsmen carved nephrite into cups, dagger hilts and fine inlaid pieces that sit in museums today.

How to choose

Look for an even colour without dark spots or cloudy patches, unless you like natural markings. Translucency at the edges adds value. The polish should be smooth and slightly greasy in look, which is typical of nephrite. Black specks are often natural chromite or magnetite and are acceptable in spinach jade.

Nephrite is commonly waxed after polishing, which is standard. Dyeing is less common than with jadeite. Serpentine, glass and dyed quartzite are frequent look-alikes. Check each listing for the treatment status as we know it.

In folk tradition across Asia, nephrite has been linked to protection and good fortune, which we mention as history.

With hardness 6 to 6.5, nephrite can scratch on quartz dust, but its toughness is remarkable and it rarely chips or breaks. It suits heavy men's rings, bangles and carvings. Clean with warm soapy water and a soft cloth.