Tunch and Melting Loss: Measuring Karigar Gold Loss
Every jewellery workshop loses some gold: in melting, filing, polishing and setting. The question is not whether there is loss, but whether it is the loss you expected. Measuring it properly starts with tunch.
What tunch means
Tunch is the purity of the metal, written as a percentage of fine gold. 22K gold is 91.6% fine, 18K is 75%, 14K is 58.5%. When you weigh metal, you need both the weight and the tunch to know how much real gold it contains.
Fine gold = weight × tunch ÷ 100
Measuring the loss
- Work out the fine gold you issued to the karigar or the melt.
- Work out the fine gold you received back, in finished pieces and scrap.
- The difference is the loss.
| Weight | Tunch | Fine gold | |
|---|---|---|---|
| Issued | 100.000 g | 91.6% | 91.600 g |
| Received | 98.500 g | 91.6% | 90.226 g |
| Loss | 1.374 g (1.50%) |
Always compare fine gold, not gross weight. If the tunch of what comes back is lower than what went out, a gross-weight check will hide a real loss.
Setting an allowed loss
Most workshops agree an allowed loss with each karigar, by process or by design. Anything above that limit is recovered or charged. To make this work:
- Record every issue and receipt the same day, with weight and tunch.
- Keep scrap, filings and dust separately and credit them back when refined.
- Compare each karigar's loss with the allowed figure every week, not at year end.
Doing it faster
Try your own numbers in the free tunch and melting loss calculator. In E-Ratna, every job bag records what went to each karigar and what came back, and the jewellery manufacturing module tracks the metal loss on every job.
