Calculation of Nisaab of Silver

Q: In the following article on your website: http://alhaadi.org.za/articles/qurbani/668-who-is-required-to-perform-q… is mentioned that "Every adult Muslim, male or female, who owns 613.35 grams of silver or its equivalent in money, personal ornaments, stock-in-trade or any other form of wealth which is surplus to his basic needs, is under an obligation to offer a Qurbani."
Can you please give the reference of Hadith or other authentic books as to how the figure of 613.35 has been deduced?

Zakaat on Various Bank Schemes

Q: Can you please advise the correct procedure for calculating Zakaat in the following situations?

  1. Murabaha Car Loan From Albaraka Bank

  2. Musharaka House Loan From Albaraka Bank for Investment Purposes

  3. Musharaka House Loan From Albaraka Bank for Personal Use

Is the total outstanding loan deducted, the loan for the year deducted or the loan for the month?

And do you first calculate how much of the property you own according to the Albaraka property share and pay zakaat on that portion only?

Women Covering their Faces In Ihraam

Q: I would like to find out that during the 5 days of Hajj, is it compulsory for women to cover the face since no clothing or cloth may touch the face. I have heard from several people that it is compulsory to cover the face even if the cloth touches the face and it would be compulsory to pay a separate amount of dumm specifically for this. Is this view correct and if so, what amount should one pay?

Zakaat If Less Than One Year Passes On The Wealth

Q: By the time of Ramadhaan when my zakaat becomes payable I will still have in my possession the money for the flights, qurbaani and spending money, none of which will have been in my possession for longer than one year, will zakaat be payable on all these monies in my possession? I have always been under the impression that zakaat is only payable if the money, jewellery, etc., is in your possession for at least one year at the designated date that one would normally pay zakaat. However, I was recently told that it would be payable if it is in your possession as at that date irrespective of the period or when it was received.