In India, there are mainly two types of ratti commonly used when describing gemstone weight. This is a common source of confusion because different traders and astrologers may use different standards. (Ratti is a traditional Indian unit of weight used to measure precious and semi-precious gemstones.)
KACHHI RATTI: Approximately 0.120 g (120 mg), which is about 0.60 carat. (Commonly used in Punjab.)
PAKKI RATTI: Approximately 0.182 g (182 mg), which is about 0.91 carat. (Commonly used in West Bengal and many other states.)
Different states in India traditionally use different standards for ratti. However, the carat is a standard unit of weight used worldwide. 1 carat = 200 milligrams (0.2 grams).