The Sunstone side quest is an extremely easy side quest that can be completed anytime after the team has escaped from the Dreadnought Leviathan, but it cannot be completed if it is raining in the Giza Plains. Check out the “Raining in the Giza Plains” tips page for more information if you have run into this problem.
Travel south from Rabanastre through the Giza Plains and back towards the Nomad Village. Speak to Masyua again and ask her to tell you more about Sunstones. She will ask you if you are interested in making some Sunstones to which you need to reply: “Sure, why not?”.
Masyua will give you a Shadestone and ask you to fill it with the light of the dark crystals and to return to her once it has turned into a Sunstone. She will mention that she pays more for “high grade” Sunstones – what she is hinting at is that she will give you a better reward the faster you are able to charge the stone and complete the quest.
Only two of the Sunstones will be lit up at any given time. Check the map if you need help finding out where they are within the Giza Plains.
The reward you receive from Masyua depends on how fast you fill the Sunstone:
Potions and a 
Holy StoneHoly Stone
You can complete this side quest as many times as you would like, but the rewards are fairly mediocre compared to the time investment, so don’t spend too much time here.
