Immortal Diamond
continued:
"That flower unseen, that gem of purest ray,
Bright thoughts uncut by men:
Strange that you need but speak them, Thomas Gray,
And the mind skips and dives beyond its ken,
Finding at once the wild supposed bloom,
Or in the imagined cave
Some pulse of crystal staving off the gloom
As covertly as phosphorus in a grave."
— From "In a Churchyard," by Richard Wilbur
"A metaphysical assertion of this kind is the idea of the 'diamond body,' the indestructible breath-body which develops in the Golden Flower, or in the square inch space."
— The Secret of the Golden Flower, by Richard Wilhelm, Carl Gustav Jung, and Hua-Yang Liu, second rev. ed., publ. by Routledge, 1999, pp. 130-131
For more about these concepts, see the work cited.