Zakat on Gold

I always had the following question which I saw answered on http://www.islameasy.org/ask_alimah_answers.php#7 so thought of sharing it in this blog.

Question
Taking Zakah based on Gold weight or its cash value
I had a zakat query - So far I have been paying zakat by :


1. Weighing the total gold I have 
2. Calculating its cash value by multiplying the weight by the market value per gram 
3. Taking 2.5% of the total cash value and paying it as zakah 


However this year I want to pay by actually selling off my gold. I want to know if the zakah will be :
a) 2.5% of the total gold weight. (so suppose I have 100 gms of gold, I will remove 2.5 grams of it as zakah and then sell it) 
OR 
b) 2.5% of the total cash value of the gold based on its weight. 


The two are different in India, because when you try to sell the gold jewelry, the jeweler pays you less than market value per gram.


Answer Bismillah
Assalamualaikum wa rahmatullah.
It is sufficient to do method a.  Calculate 2.5% of the gold in weight and either give the gold or sell it and give the cash.


The answer was checked with a Mufti.
And Allah knows best. 
Alimah, 
Fatwa Department, IslamEasy.org