“Certain ones of our people wrote to abu al-Hassan, the previous one (a.s.), asking about Salah (prayer) on glass. He has said that when my letter finished I thought and said to myself that it is something that grows from earth, so I do not need to write and ask him (the Imam). He (the Imam) wrote to me, ‘You must not perform Salah (prayer) on glass even though your soul has spoken to you that it is of what earth grows. However, it is from salt and sand and they both are metamorphosed.’”