Probably borrowed from a language in Central Asia during the Han Dynasty. The Book of Han:
出封牛、水牛、象、大狗、沐猴、孔爵、珠璣、珊瑚、虎魄、璧流離。
(The country of Jibin in the Western Regions) produces bison, buffalo, elephants, big dogs (kuchis?), macaques, peacocks, jewels, corals, ambers and cat's eyes.
Compare Persian کهربا(kahrobâ, “amber, straw-attractor”), Turkish kehribar(“amber”).