Author Topic: Testing the Purity of Metal the old traditional way!!!  (Read 7671 times)

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Offline Abhay

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Testing the Purity of Metal the old traditional way!!!
« on: February 20, 2012, 04:33:28 AM »
With the development of Science and technology, many new methods and equipment have been found to ascertain the exact composition of a metal - like Xray Spectroscopy,  carat meter, Non-destructive testing etc. etc., but when it comes to old traditional Indian Jewelers,
a simple black stone is the "EQUIPMENT" used to ascertain the purity of the Gold.

KASAUTI Stone, a jet black stone,  is often used by old Indian Jewelers to test the purity of the metal. The metal to be tested is rubbed against the Stone, and by the colour of the streak, the metal leaves on the stone, an experienced jeweler can immediately have an idea of the purity of the gold or silver.

In the third image enclosed, you can see the three distinctive streaks left by Gold, Silver and Copper on the stone.

Most probably, as I have heard from a jeweler, this particular stone comes from a river bed from NEPAL. I found one such stone being sold by a woman on the footpaths of Chandani Ckowk in Old Delhi, for Rs. 250 ($ 5.00).

This method of testing has been used since centuries.


Offline Figleaf

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Re: Testing the Purity of Metal the old traditional way!!!
« Reply #1 on: February 20, 2012, 02:05:16 PM »
Thanks, engipress. A very worthwhile addition. In European history, the same method was used. A piece of basanite (touchstone) was used to determine metal and precious metal content.

An unidentified coin is a piece of metal. An identified coin is a piece of history.