The jewel in the Lotus; Om mani padme Om.
On a large scale; the Light that shines in the darkness after the Big Bang; The Spirit.
On a smaller scale the human spirit shining within the body;
I put a jewel on thy forehead. Eze 16:12
The imperishable jewel of a gentle and quiet spirit, 1Pe 3:4
You were marked in him with a seal, the promised Holy Spirit. Eph 1;13
An other word for this Jewel is the eye.
The Hebrew word Ain means eye, but also stands for a spring or a well; that is to say, the place were the Light enters the body.
The light of the body is the eye.
Therefore, when thine eye is One (single),
(one; in unity; jechida, when soul and spirit are in unity with God.)
thy whole body also is full of light.
But when thine eye is evil, thy body also is full of darkness. Lu 11:34
In the book of Revelations (14;9, 20;4), people who worship the beast receive a mark on their forehead which may be the extinguished Crown and/or forehead chakra. It is because of this that the forehead; the brow is blessed repeatedly during an exorcism.