The Gem of Gentle Mind is an essence gem which grants bonuses to Mind and Intuition. It is exclusive to followers of the Way of the Open Palm, but another gem, the Gem of Evil Thought, can provide the same bonuses to a follower of the Way of the Closed Fist.
It is found at random.
In-game description: "This gem radiates peace and serenity, reflecting the past owners, who imprinted fragments of their own thoughts on it. This is a gem of enlightened scholars and philosophers, men and woman at peace with themselves and their place in the world. Their tranquility and peace of mind is passed on to those capable of tapping into the gem's power."