Behold our unassuming Mission. Pure and simple as the very first waters! Brother Ansel and I devote our hours to shards and gems, while the others tend garden and shrine. All of us pray upon our beads.
It is a beautiful lesson in the ways of Mitharu. Each gem carries within in his influence. Untouched, you can see the Light of Peace working in a perfect symphony. A shard is but one raw image if this perfection - refined by our imperfect hands.
When you first meet Brother Gamian, he asks if you worship Mitharu. You can lie to him and say you do (95% success with Persuasion 3), or you can say you don't, the third option is "I follow my own path"
You can buy shards and gems from him regardless of your answer, and his prices are no lower if he thinks you're a worshiper.
If you lie to him, he says you'll be welcome in all of Mitharu's homes, so maybe this affects other NPC's reaction towards you (unconfirmed).