How is the 2 mehr (minimum and Faatimi) calculated? Is it on the rate,eg.gold price, multiplied by some quantity-please detail how do you arrive at the quoted figures?

NISAAB TIME%0D%0AThe payment of Zakaat is compulsory on the excess wealth or effects which is%0D%0Aequal to%2For exceeds the value of Nisaab and which is possessed for a full%0D%0AISLAMIC YEAR. If such wealth decreases during the course of the year, and it%0D%0Aincreases again to the value of Nisaab before the end of the year, then the%0D%0AZakaat must be calculated on the full amount that is possessed at the end of%0D%0Athe year.%0D%0A%0D%0ANISAAB OF GOLD AND SILVER AS FIXED BY RASULULLAH (Sallallaahu %C1layhi%0D%0AWasallam).%0D%0A%0D%0ANisaab Grams Tolas Grams Troy Oz.%0D%0AGold 20 Mithqaals 87.48 7.5 1350 2,8125%0D%0ASilver 200 Dirhams 612,36 52.5 9450 19,6875%0D%0A%0D%0ANote: If the price of Gold or Silver increases, then one has to pay on the%0D%0Aincreased prices%0D%0A%0D%0AThe rate of Zakaat which was fixed by Rasulullah (Sallallaahu %C1layhi%0D%0AWasallam) is 2.5% i.e. 2.5 cents in a Rand%0D%0A%0D%0AHereunder follows a step by step sequence of calculating the Zakaat Nisaab,%0D%0AMehr Faatimi and the minimum Mehr.%0D%0A%0D%0A1. Phone the Rand Refineries at (011) 873 2222 and ask for Jewellery sales%0D%0Aon extension 2094.%0D%0A2. Request the price of Gold and Silver per gram including VAT. Assume the%0D%0Aprice is R50.00 and R0.70 respectively.%0D%0AThe Nisaab of Silver is 612,36 grams of Silver is multiplied by 70c to give%0D%0Aus a value of R 428.65. The Nisaab for Gold is 87.48 grams.%0D%0A3. Minimum Mehr is 30.618 grams of Silver. This is also multiplied by 70c to%0D%0Agive us a value of R21.43.%0D%0A4. Mehr Faatimi is 1530 grams of Silver. This is also multiplied by 70c to%0D%0Agive us a value of R 1071.63.%0D%0A%0D%0ACalculated for South Africa.%0D%0A