The resale value of platinum depends on the quality and what type it is. Diamonds rate doesn't increase or decrease very rapidly like the prices of gold, but they are very much like the constant and depends upon the demand and supply. If you are reselling only platinum coins, then you will get money as per the market rates at that instant. The platinum rate for 10 gram is 27,500/- on today’s date. Now if you are reselling it then obviously you'll get value as according to market rates.