Curious Coin

Curious Coin is a currency used to purchase items sold by Xur'ios at the Antonidas Memorial in Dalaran.

Source
The coins can be obtained from the following places:
 * Rare spawns in the Broken Isles and Argus
 * Treasure chests in the Broken Isles and Argus
 * Emissary cache - from completing 4 World Quests
 * Paragon cache - for reaching every 10,000 paragon reputation (post ) with a faction
 * Mythic+ Challenger's Cache
 * Winning battlegrounds
 * Bosses in Invasion Points, dungeons, and raids (including world bosses)