The Crystal Window

Maria virginitas fuit multipliciter privilegiata. A patriarchis quisbusdam operibus praefigurata. Praefigurata enim fuit in fenestra crystallina, quam Noe fecit in arca secundum quod tradunt Hebraei, quae excludebat aquam crystallina, suscepta aliunde luce. Arca Maria, fenestra crystallina euius virginitas, quae excludit ab ea aqua carnalium voluptatum, et qua digna fuit in se suscipere Christum lucem veram. Unde eleganter dicit quidam: Si crystallus fit humesta, atque soli fit subiecta, scintillat igniculum. Nec crystallus nec in partu soluitur pudoris signaculum Sanctus Albertus Magnus, De Laudibus Beatae Mariae Virginis, Liber Quartus, De Virtutibus Mariae, Caput IX, De Virginitate Mariae Source: Here, p113

The virginity of Mary was privileged in many ways. She was prefigured by certain works of the patriarchs. Indeed she was prefigured by the crystal window which Noah made in the ark according to the traditions of the Hebrews, which crystal excluded the water and received light from elsewhere. Mary is the ark, the crystal window is her virginity, which kept from her the water of carnal pleasure and by which she was worthy to receive Christ into herself, the true light. Whence elegantly it has been said that if crystal is moistened and exposed to the sun, it flashes with sparks. The crystal does not dissolve, nor does the seal of modesty in her delivery. Saint Albert The Great, On the Praises of The Blessed Virgin Mary, Book 4, On The Virtues of Mary, Chapter 9, On The Virginity of Mary