Yuga-Vibhāga and Kāla-Pramāṇa
Measures of Time and the Four Yugas
चक्रं रथो मणिर्भार्या निधिरश्वो गजस्तथा / सप्तैतानि च रत्नानि सर्वेषां चक्रवर्तिनाम
cakraṃ ratho maṇirbhāryā nidhiraśvo gajastathā / saptaitāni ca ratnāni sarveṣāṃ cakravartināma
The Wheel, the Chariot, the Jewel, the Queen, the Treasure, the Horse, and the Elephant—these seven are the ratnas of all Cakravartins.