Purity
"Brave Knights dwell in the castle of Montsalvatge , where the Grail is kept. There are the Templars, who often ride far in search of adventures [.] In this castle live a troop of high-minded warriors. I want to tell you how they are nourished: all of the food that is served to them is provided from a precious stone whose essence is completely pure. If you do not know it, I will tell you its name: it is called lapsit exillis". (W. von Eschenbach, Parzifal)
"Who shall present to the Highest a mirror of love and purity so that he lives again among us in the primary and ultimate splendour? Our virgin has conceived under the gaze of the Highest and she has given us a son who has vanquished death and who shall make all his crippled brethren perfect" (L. Cattiaux, The Message Rediscovered 18, 68)
"You know that our mercury is openly visible to all men, although it is only known by a few. It is when it is preparing its splendour that it is most admirable; but its vision is only conceded to the children of knowledge. Do not despise it, even though you might, see it under sordid appearances. For it you do that, you will never be able to realize our mastery; and if you can change its being, the transformation will be glorious, as our water is a purest virgin" ( Ireneus Philalethes , Open Entrance to the Closed Palace of the King)
"The substance that is used for the preparation of the Arcanum must be pure, indestructible and incombustible. It should be purified of all gross material elements, be immune to doubt and be proved against the fire of passions". (H. Madathanas, in a Treasury of Traditional Wisdom by W. Perry)