I have heard that the word tsohar used for "window" in Genesis 6:16 may be interpreted instead as a "precious stone" that may have provided light within the ark. Here is the text from the KJV of Genesis:
A window shalt thou make to the ark, and in a cubit shalt thou finish it above; and the door of the ark shalt thou set in the side thereof; with lower, second, and third stories shalt thou make it. Genesis 6:16
Is anyone aware of any commentary that may support this interpretation? I would like to know of any references to rabbinical sources if there are any. Thanks!