WoWDB

The  Bottle of Airspark can be found beside Lanna Skyspark, but trying to take it will earn you a rebuke from Lanna and you are forced to pay money for it.  She is found outside and northwest of the main building in Thunder Totem, on the bottom ground.

From there, follow the path leading north.  The  Darkshard Crystal is located right on the trail, but attempting to collect it will summon a Darkshard Crystal which must be killed.

Once done with that, go back the way you came and take the short trail leading to the stream.  Follow it east until you come up to the bottom of the waterfall, where there'll be a pack of Turbulent Lifefury in the way.  You will need to kill at least the one closest to the quest object before you collect  Mu'sha's Tears.