ANSWER:

Because Allah mandated that zakat is due only on gold, silver and cash. If you are trading in them, there is zakat. 

Why is there no Zakah on pearls and diamonds?

Zakat | February 22, 2018 7:49 am
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I am fron Bangladesh. Here in Bangladesh, madrasa (school for islamic teaching) are mostly run by peoples donation and mostly the orphan and the child from poor background go there. Can i donate my Jakat money to a madrasa or it must be given to the poor peoples hand.
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Do we need to pay zakat on jewellery which is used 2 to 3 times a year only – for big occasions.