There are two regular missions that will drop them too (the others listed are discovery missions) :
Runaway Ship
◾Mission Brief: Just as a ship in your sector jumped to lightspeed, an alert from Imperial Command named it as transporting stolen Sith relics. Have a companion track it down.
◾Completion:Vette computed the runaway ship's destination, followed, infiltrated and sabotaged it until Imperial Command could send troops, earning a generous reward.
◾Time: 14m 10s
◾Cost: 470cr
◾Reward: Moderate Yield: Grade 3 Gemstones ◾Tatooine Flamegem x4; Krayt Dragon Pearl x2
◾Tatooine Flamegem x2
I was Somebody Once
◾Mission Brief: A drunk in a Klatooine cantina is selling an old tracking device, claiming it leads to fabulous wealth. For a few credits, your companion could find out.
◾Completion: Vette followed a mysterious signal with the tracking device. It led to a Klatooine's south pole, and a derelict starship filled with valuables!
◾Time: 20m 36s
◾Cost: 575
◾Reward: Abundant Yield: Grade 3 Gemstones ◾Immaculate Yellow Crystal x2; Tatooine Flamegem x4; Krayt Dragon Pearl x3