The Eighth Foundation Stone of the Heavenly Jerusalem is Beryl.
"Beryl. The beryl is as if thou shouldest imagine water to be struck by the rays of the sun, and to give out a ruddy and beautiful colour. But it does not shine unless it is shaped by polishing to an hexangular form. For the reflected brightness of the angles is intensified. But it signifies men who are naturally sagacious in intellect, but who shine the more by the light of heavenly grace."
[The Explanation Of The Apocalypse, by St. Bede the Venerable, 7th Century Doctor Universalis]