If you are interested in the ancient history of gold, here are some interesting facts about its measurement. In ancient India, gold was weighed with the help of Gunja or Ratti seed because the seed is fairly constant in weight.
In India the system is BIS Hallmark which certifies that the piece of jewellery adheres to a set of standards laid by the Bureau of Indian Standards (BIS). The hallmarking is done at the BIS Authorized Labs where the gold or silver in every piece is individually tested for its purity and if found correct, a mark is put on it by laser machine.
The measure Ratti is equal to one seed.
The other standardizations are as follows
The botanical name of this seed is Abrus Precatorious and it is from the Fabaceae i.e pea family. It is called Coral bead vine, Rosary pea in English, Ratigedi in Nepali, Gunchi in Hindi, Gunjaa in Sanskrit, Gulugunji in Kannada, Gunch in Bengali, Ratti in Gujarati, Kundu mani in Tamil, Gunja in Marathi and Kaincha in Oriya.
Gunja seeds are 6 to 7 mm long scarlet seeds with black bases. There are 4 to 6 seeds in a pod. Because of their vibrant colour combination and attractive look they are used in the native jewellery, too.