|Unit system||Indus Valley Civilization, Mahajanapadas, Arthashastra, Mughal empire|
|1 in ...||... is equal to ...|
|SI units||0.1215 g|
|Metric system||0.91 ct|
Ratti (Sanskrit: raktika) is a traditional Indian unit of measurement for mass. Based on the nominal weight of a Gunja seed (Abrus precatorius), it measured approximately 1.8 or 1.75 grains or 0.1215 g as modern standardized weight. It is still used by the jewellers in the Indian Subcontinent.
Ratti based measurement is the oldest measurement system in the Indian subcontinent, it was highly favoured because of the uniformity of its weights. The smallest weight in the Indus Valley civilization was equal to 8 rattis, (historically called Masha). The Indus weights were the multiples of Masha and the 16th factor was the most common weight of 128 Ratti or 13.7 g.
A unit called Śatamāna, literally a 'hundred standard', representing 100 krishnalas is mentioned in Satapatha Brahmana. A later commentary on Katyayana Srautasutra explains that a Śatamāna could also be 100 rattis. A Satamana (Śatamāna, literally "hundred measures") was used as a standard weight of silver coins of Gandhara between 600–200 BCE., rest of the Indian currency weights like Karshapanas were also based on the weight of ratti. Gold coins excavated from southeast Asia have been analysed as following the ratti based weight system as well.
During the period of Kautilya, the 32 ratti standard was called as Purana or Dharana which was in vogue before the Mauryan empire, but Kautilya provides a new standard of 80 ratti called Svarna, which was widely adopted from that time onwards. The ball weights from jeweller's hoard discovered from Taxila conform to the 32 ratti standard also called Purana by Kautilya, while the Mathura weights (Dated from 1st century BC-2nd century AD) with Brahmi numeral 100 (100 svarna or 100 karsha) conforms with the new svarna standard.
Mughal empire employed Ratti as a unit of measure for the weight of precious stones such as diamonds. Around 1665 the Shah’s son, Aurangzeb, showed a diamond to the famous jeweler and world traveler Jean Baptiste Tavernier. At that time Tavernier wrote in his Six Voyages:
"The first piece that Akel Khan (Chief Keeper of the King's jewels) placed in my hands was the great diamond, which is rose cut, round and very high on one side. On the lower edge there is a slight crack, and a little flaw in it. Its water is fine, and weighs 319-1/2 Ratis, which makes 280 of our carats, the Rati being ⅞th of a carat."
Following info provides the unit conversion from ratti to other units in traditional Indian system of measurements
- 1 Tola = 12 Masha or 11.664 g
- 1 Tank = 4 Mashas or 3.888 g
- 1 Masha = 8 Ratti or 0.972 g
- 1 Ratti = 8 Rice
- 1 Satamana = 100 Rattis / 11 g of pure silver
- 1 Karshapana = 32 Rattis/ 3.3 g of pure silver
- ½ Karshapana = 16 Rattis
- ¼ Karshapana (masha) = 8 Rattis
- 1/8 Karshapana = 4 Rattis
- 4 Dhans = 1 Rati
- 6 Rattis = 1 Anna
- 8 Rattis = 1 Masha
- 12 Mashas = 1 Tola or Bhari
- 16 Annas = 1 Tola
- 1 Ratti (sunari) goldsmith = 121.5 mg
- 1 Pakki Ratti (for astrological gemstones ) = 1.5 x Sunari Ratti = 1.5 x 121.5 mg = 182.25 mg = 0.91 Carat
- 1 Ratti = 0.91 carat
- Mukherjee, Money and Social Changes in India 2012, pp. 412–413.
- Cunningham, Coins of Ancient India 1891, pp. 22–23.
- McIntosh, Jane (2008). The Ancient Indus Valley: New Perspectives. ABC-CLIO. ISBN 978-1-57607-907-2.
- Mukherjee, Money and Social Changes in India 2012, p. 412.
- Borell, Brigitte. "Gold Coins from Khlong Thom". Journal of the Siam Society. 105: 157.
- Allchin, F. R. (1964). "An Inscribed Weight from Mathurā". Journal of the Economic and Social History of the Orient. 7 (2): 201–205. doi:10.2307/3596241. ISSN 0022-4995. JSTOR 3596241.
- Cunningham, Alexander (1891), Coins of Ancient India: From the Earliest Times Down to the Seventh Century A. D., London: B. Quaritch
- Mukherjee, B. N. (2012), "Money and Social Changes in India (up to c. AD 1200)", in Saiyid Zaheer Husain Jafri (ed.), Recording the Progress of Indian History: Symposia Papers of the Indian History Congress, 1992-2010, Primus Books, pp. 411–, ISBN 978-93-80607-28-3