In South Asia: a small weight used for expressing the weight of gems, equal to one-eighth of a masha.
The size of the weight has varied. In 1833 it was officially fixed in British India at 1⅞ grains (approx. 121 mg). A double unit appears to have been in use in earlier times.
Early 17th century; earliest use found in Samuel Purchas. From Hindi rattī, the seed of the jequirity (Abrus precatorius, a leguminous creeping plant) from Sanskrit raktikā from rakta red, use as adjective of past participle of rañj- to become reddened + -ika, diminutive suffix.